Move schemas to Schemas namespace
move Schema specs to Schemas folder
remove schema from spec file names
Raise an error if there are unmatched keys
Allow a schema to be extended
Only raise missing key errors when strict checking

This is to remain backwards compatible
Merge pull request #1 from jfoley/master

Pulling this in with the last commit. Per offline discussion with cloud foundry team, we need to maintain backwards compatibility (I believe this gem is primarily used in the cloud controller and the dea) so strict key checking needs to be opt-in.