Column family support in RocksJava

This commit includes the support for the following functionalities:
  - Single Get/Put operations
  - WriteBatch operations
  - Single iterator functionality
  - Open database with column families
  - Create column family
  - Drop column family
  - Properties of column families
  - Listing of column families
  - Fully backwards comptabile implementation

In addition there is an additional Java sample which can be build
using "make cfsample".

What is not supported currently using RocksJava:
  - Multi Iterator support
  - MultiGet

I decided to file a pull request w/o the missing two features to omit
some merging trouble.

The following targets work as expected:
  - make rocksdbjava
  - make jtest
  - make cfsample

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