ST_MakeGrid and ST_MakeGridPoints

With this PR, we add  the following create functions:

 * ST_MakeGrid replaces the ST_CreateGrid function
 * ST_MakeGridPoints replaces  ST_CreatePointsGrid function

The signatures are

```java
ST_MakeGrid('tableName', deltax, deltay); or ST_MakeGrid((select the_geom from aSpatialTable) deltax, deltay);
```

Note :   the user cannot set an angle to rotate the grid because we consider that this job can be solved with a post SQL process.

and

```java
ST_MakeGridPoints('tableName', deltax, deltay); or ST_MakeGridPoints((select the_geom from aSpatialTable) deltax, deltay);
```

Note :   the user cannot used a polygon mask to create the points only in a polygon. This operation will be done in the future using a specific function...

In order to simplify SQL spatial uses new SFSUtilities have been added : 

```java 
 * getGeometryFields(ResultSet resultSet)
 * hasGeometryField(ResultSet resultSet)
 * getResultSetEnvelope(ResultSet resultSet)
 * getResultSetEnvelope(ResultSet resultSet, String fieldName)
```