Update gems to latest keeping Rails on 3.2.x

fixes #11
Define base Shavar to handle chunk deletes

fixes #11
Add and Sub shavars inherit from Shavar

fixes #11
Ensure ChunkList can convert text lists to arrays

fixes #11
Define ChunkList to convert list strings to arrays

fixes #11
Response Helper delegates chunk deletion to models

and leans on the ChunkList to handle list conversions
instead of the ChunkHelper

fixes #11
Remove unused ChunkHelper#chunklist_to_sql

fixes #11