[RocksJava] Column family support

This commit includes the support for the following functionalities:

 - Single Get/Put operations
 - WriteBatch operations
 - Single iterator functionality
 - Open database with column families
 - Open database with column families Read/Only
 - Create column family
 - Drop column family
 - Properties of column families
 - Listing of column families
 - Fully backwards comptabile implementation
 - Multi Iterator support
 - MultiGet
 - KeyMayExist
 - Option to create missing column families on open

In addition there is are two new Tests:

 - Test of ColumnFamily functionality
 - Test of Read only feature to open subsets of column families
 - Basic test to test the KeyMayExist feature

What is not supported currently using RocksJava:

 - Custom ColumnFamilyOptions

The following targets work as expected:

 - make rocksdbjava
 - make jtest

Test environment: Ubuntu 14.04(LTS, x64), Java 1.7.0_65(OpenJDK IcedTea 2.5.2), g++ 4.8.2, kernel 3.13.0-35-generix
Merge pull request #319 from fyrz/column_families_java

Column family support in RocksJava