Add support for multiple column families in Get, Put and Delete requests

[adityakishore]

HBase supports row level consistency which means reads and updates to concerning a single row but containing multiple column families will see a consistent view of the row if sent as a single RPC.

AsyncHBase library currently lacks this feature.

[adityakishore]

Patch available at adityakishore@cef2cdc. Applies on top of tsuna@bc1db42

[adityakishore]

Closing as duplicate of #76