kv.rb new features

Added option to parse value between brackets.
When spaces attached to a value_split ignore the spaces.
Added new feature to drill down (dig) into value and extract more key-value pairs automatically.

New test for this has been added and other tests has been changed as well to check the above changes. 
Hi, the keys with spaces was there at the begining.
About dig values, 
Its differ from using multiple kv filters if you don't really know which keys you have and you want to be as dynamic as you can..
I found it useful when I want to index new kind of logs which didn't written by me.
Can you suggest another name instead of "dig"?