Listing of changes

- JavaDoc readability of RocksObject JavaDoc
- JavaDoc improvements BlockBasedTableConfig, GenericRateLimiterConfig, RocksDB
- JavaDoc improvements MemTableConfig
- JavaDoc improvements RocksObject
- JavaDoc improvements GenericRateLimiterConfig
- JavaDoc improvements ReadOptions
- JavaDoc improvements RateLimiterConfig
- JavaDoc improvements RestoreOptions
- JavaDoc improvements RestoreBackupableDB
- JavaDoc improvements BlockBasedTableConfig
- JavaDoc improvements Options
- JavaDoc improvements BackupableDB and BackupableDBOptions
Fixed Findbugs issues

- BackupableDB missing call to super.finalize(major)
- WriteBatchTest inefficient String usage(minor)
- RocksDB local dead variable store(medium)
Lint changes
Merge pull request #331 from fyrz/findbug_issues

Fixed Findbugs issues in RocksJava
Merge pull request #334 from fyrz/JavaDoc-Cleanup

JavaDoc fixes & enhancements RocksJava
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

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. I would propose to hand them over to a later point
of time.
Quality improvements
- Replaced all NULL occurences in code with nullptr
- Removed iostream include
Fixed some lint problems
More lint problems fixed
Moved Testing code from Sample to Test.
Fixed line length in Test
Merged RocksDB.java to current upstream/HEAD