V2 client implementation with ~80% tests passing
More, query-related specs passing
All tests pass using the ClientV2 API
Cache table schema data
Merge branch 'clientv2' of git://github.com/loganb/Dynamoid into 0.7.x

This accepts PR https://github.com/Veraticus/Dynamoid/pull/154

Conflicts:
	lib/dynamoid/adapter.rb
	lib/dynamoid/document.rb