Feature: SQL Cobol support through dbpre

This PR implements feature request #82. 

Now you can edit, compile and run sql cobol files (.scb)!

### How to upgrade OpenCobolIDE to test this feature?

1) upgrade pyqode.cobol from its ``sql`` branch:

```pip install git+https://github.com/pyQode/pyqode.cobol.git@sql --upgrade``` 

2) install OpenCobolIDE from the ``sql`` branch:

```pip install git+https://github.com/OpenCobolIDE/OpenCobolIDE@sql  --upgrade```

Note that if you installed OpenCobolIDE in development mode, as suggested in the [wiki](https://github.com/OpenCobolIDE/OpenCobolIDE/wiki/Setting-up-a-development-environment), you just have to checkout and pull the ``sql`` branch).

### Installing dbpre

Follow the instruction in the [readme](http://sourceforge.net/p/dbpre/code/HEAD/tree/README.TXT). You don't need to install it system wide, just compile everything in place and use that directory to configure OpenCobolIDE as explained in the below section.

### Configuration:

1) You must setup OpenCobolIDE to work with dbpre: Edit->Preferences->SQL Cobol:

![sql-cobol-preferences](https://cloud.githubusercontent.com/assets/1681217/5539538/2a0ea426-8ac3-11e4-8806-7ae4ff8a6c7d.png)

2) You must configure the compiler to link with libmysqlclient (-l and -L option):

![compiler-config](https://cloud.githubusercontent.com/assets/1681217/5539540/317764aa-8ac3-11e4-8b08-942c9d712a05.png)

3) Now you can compile and run a .scb file

![example-running](https://cloud.githubusercontent.com/assets/1681217/5539542/383ee650-8ac3-11e4-8f0b-f91ebdc742f8.png)

you can see the compilers (dbpre and cobc) output in the application log (?->About OpenCobolIDE->Log)

![log_output](https://cloud.githubusercontent.com/assets/1681217/5539551/4cbb6b6c-8ac3-11e4-90cf-e221f556431d.png)


### Example

**this example come included with dbpre**

```cobol
----+-*--1----+----2----+----3----+----4----+----5----+----6----+----7-*--+----8
      **************************************************************************
      *  I D E N T I F I C A T I O N   D I V I S I O N                         *
      **************************************************************************
        IDENTIFICATION              DIVISION.
        PROGRAM-ID.                 PCTB003B.
        AUTHOR.                     THE_PIPER.
        DATE-WRITTEN.               TODAY.
      /
      **************************************************************************
      *  D A T A    D I V I S I O N                                            *
      **************************************************************************
        DATA                        DIVISION.
      /
      **************************************************************************
      *  W O R K I N G   S T O R A G E   S E C T I O N                         *
      **************************************************************************
        WORKING-STORAGE SECTION.
      *
      * The needed working storage stuff for the framework
        COPY PGCTBBATWS.
      *
      * This will be displayed in the logfile at runtime
        01  PGCTB-VERSION                    PIC  X(38) 
            VALUE '20120426 1.0 INITIAL RELEASE'.
      *
        01  FIELD1.
          05 FIELD1-NUM                      PIC  9(08).
          05 FILLER                          PIC  X(12) VALUE SPACE.
        01  FIELD2                           PIC  X(16).
        01  FIELD3                           PIC  X(32).
      *
        01  T                                PIC  S9(9) COMP.
      *
      * The communication area for the database
        EXEC SQL
             INCLUDE SQLCA.
        END-EXEC.
      /
      **************************************************************************
      *  P R O C E D U R E   D I V I S I O N                                   *
      **************************************************************************
        PROCEDURE DIVISION.
      * The framework itself, calling PGCTB-ACTION to run the users coding
           EXEC SQL
               INCLUDE PGCTBBAT REPLACING 'TTTTNNNB' BY 'PCTB003B'.
           END-EXEC.

      /
      **************************************************************************
      *  P O C T B - A C T I O N   S E C T I O N                               *
      **************************************************************************
        PGCTB-ACTION SECTION. 
      *
           DISPLAY 'In PGCTB-ACTION.'
      *
      *    EXEC SQL
      *       ROLLBACK
      *       please dont parse this...
      *    END-EXEC
      *
      *
           PERFORM DISPLAY-ALL-RECORDS
      *
           DISPLAY 'Delete entire table'
      * 
           EXEC SQL
              DELETE
              FROM example_table
           END-EXEC.
           EVALUATE TRUE
             WHEN DB-OK
                CONTINUE
             WHEN OTHER
                PERFORM DB-STATUS
           END-EVALUATE
      *
           DISPLAY 'Insert new records'
      * 
           PERFORM VARYING T FROM 1 BY 1 UNTIL T > 10
              MOVE T                   TO FIELD1-NUM
              EXEC SQL
                 INSERT 
                 INTO example_table
                     (
                        FIELD1, 
                        FIELD2, 
                        FIELD3
                     )
                     VALUES
                     (
                         :FIELD1 ,
                         'Value2' ,
                         'Value3'  
   
                  )
              END-EXEC.
              EVALUATE TRUE
                WHEN DB-OK
                   CONTINUE
                WHEN OTHER
                   PERFORM DB-STATUS
              END-EVALUATE
           END-PERFORM   
      *
           PERFORM DISPLAY-ALL-RECORDS
      * 
           DISPLAY 'Update the first record'
      * 

           EXEC SQL
              UPDATE example_table
              SET FIELD1 = 'UpdatedValue1'
              WHERE FIELD1 = '00000001'
           END-EXEC.
      * 
           DISPLAY 'Update the third record'
      * 

           EXEC SQL
              UPDATE example_table
              SET FIELD1 = 'UpdatedValue3'
              WHERE FIELD1 = '00000003'
           END-EXEC.
      *    DISPLAY 'SQLCA-STATEMENT=' SQLCA-STATEMENT
      *    DISPLAY 'SQLCODE=' SQLCODE
      *    DISPLAY 'SQLCA-COUNT=' SQLCA-COUNT
           EVALUATE TRUE
             WHEN DB-OK
                CONTINUE
             WHEN OTHER
                PERFORM DB-STATUS
           END-EVALUATE
      * 
           PERFORM DISPLAY-ALL-RECORDS
      * 
           DISPLAY 'Ende PGCTB-ACTION.'
      *
           .
        PGCTB-ACTION-EXIT.
           EXIT.
      /
      **************************************************************************
        DISPLAY-ALL-RECORDS SECTION. 
      *
            DISPLAY '-------------------------------------------'
      * Attention !! Table name is CaSe sensitive!!!!!!!!!!!!!
            EXEC SQL
               DECLARE ALLROWS CURSOR FOR
               SELECT FIELD1, FIELD2, FIELD3
               INTO :FIELD1 :FIELD2 :FIELD3
               FROM example_table
            END-EXEC.
            EVALUATE TRUE
            WHEN DB-OK
               CONTINUE
            WHEN OTHER
               PERFORM DB-STATUS
            END-EVALUATE
      *
            EXEC SQL
               OPEN ALLROWS
            END-EXEC.
            EVALUATE TRUE
            WHEN DB-OK
               CONTINUE
            WHEN DB-NOT-FOUND
               CONTINUE
            WHEN OTHER
               PERFORM DB-STATUS
            END-EVALUATE

            DISPLAY  'FIELD1=' FIELD1 ' FIELD2=' FIELD2 
                     ' FIELD3=' FIELD3
          
            PERFORM UNTIL NOT DB-OK
               EXEC SQL
                  FETCH ALLROWS
                  INTO :FIELD1 :FIELD2 :FIELD3
               END-EXEC.
               EVALUATE TRUE
                 WHEN DB-OK
                     DISPLAY  'FIELD1=' FIELD1 ' FIELD2=' FIELD2 
                           ' FIELD3=' FIELD3
                 WHEN DB-NOT-FOUND
                    MOVE SPACE             TO FIELD1
                    MOVE SPACE             TO FIELD2
                    MOVE SPACE             TO FIELD3
                 WHEN OTHER
                    PERFORM DB-STATUS
               END-EVALUATE
            END-PERFORM
            SET DB-OK                      TO TRUE
            DISPLAY '-------------------------------------------'
      *
            EXEC SQL
               CLOSE ALLROWS
            END-EXEC.
            EVALUATE TRUE
            WHEN DB-OK
               CONTINUE
            WHEN OTHER
               PERFORM DB-STATUS
            END-EVALUATE
           .
        DISPLAY-ALL-RECORDS-EXIT.
           EXIT.
```

To use that program, you need to create a database called ``testdb`` and a table called ``example_table``:

``` sql
CREATE TABLE example_table (
   field1 char(20),
   field2 char(16),
   field3 char(32));
```