Updated Resource Class API

Add transactions to the database operations
Add GET and DELETE operations
Support association of Racks in POST operation
Starts work on nested marshalling
Merge pull request #10 from mtaylor/resource_class_updates

Updated Resource Class API
Add entry points to the API

GET / and GET /v1/ now return basic metadata. The look and feel is
in line with the other OpenStack APIs, albeit more spare.

Signed-off-by: Tomas Sedovic <tomas@sedovic.cz>
Merge pull request #12 from tomassedovic/entrypoints

Add entry points to the API
Initial support for updating Rack