* Update library to support column families. If not specified, uses the 'default' column family.

* Added tests for column family changes.

* Update library version and readme.

* Updated the librocksdb c library to the latest stable version.

* Started rewrite of library.

* Commit library rewrite progress.

* Completed initial rewrite and refactored tests.

* Completed implementation of backup engine.

* Added tests for new types.

* Completed tests for existing features.

* Remove features not supported by older versions of RocksDB to fix CI (temporary fix).

* Remove flush before backup support from BackupEngine to fix CI.

* Update library to support column families. If not specified, uses the 'default' column family.

* Added tests for column family changes.

* Update library version and readme.

* Updated the librocksdb c library to the latest stable version.

* Started rewrite of library.

* Commit library rewrite progress.

* Completed initial rewrite and refactored tests.

* Completed implementation of backup engine.

* Added tests for new types.

* Completed tests for existing features.

* Remove features not supported by older versions of RocksDB to fix CI (temporary fix).

* Remove flush before backup support from BackupEngine to fix CI.

* Implemented RocksDB iterator.

* Implemented pairs iterator.

* Completed implementation of WriteBatch with tests.

* Fix example code.

* Completed implementation of TransactionDb.

* Support setting default column family.

* Remove unneeded usage of var for ref type parameters.

* Completed transactiondb tests.

* Improve and refactor rocksdb test.

* Create ColFamilyReadOnly and ColFamilyReadWrite types for using a specific column family.

* Use inline pragma for small procs and add lock to RocksDbRef type close to prevent double free.

* Added documentation for the public API.

* Initial implementation of sst filewriter.

* Added tests for sstfilewriter.

* Documentation minor improvements.