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. 
Would prefer to see keys with a space to be converted into keys with a '_' ( underscore )

@jordansissel @colinsurprenant what do you guys think?