merge with asynchase 1.5

@jasonculverhouse @canoeberry 
Guys, please take a look if you can. 
Jonathan, the merge takes away your change: 

https://github.com/Flipboard/asynchbase/commit/3dcbcd3ccf611327a305a594c1eee8052dc31f97 (only ask for protocol version ONCE). It seems the hellorpc in RegionClient takes care of that.