removed extraneous files and updated SDK to version 0.912

1. DRY versioning via the version.rb file.
2. restricted access to urls to graph.goplay.com and
test-graph.goplay.com, accessible through is_test on the PublisherSDK.
3. added a user agent header.
4. SDKException gets a type and url for richer error reporting.
5. PublisherSDK token handling is more sophisticated.  Stores token in a
hash kept as a class variable to be persisted between requests. If a
token fails due to staleness, allows two retries to retrieve a token and
the data from our system before throwing an exception.
6. extend_endpoint now creates a new SDK to prevent artifacts being left
from requests that were never sent.
7. construct_request needs to add a segment when the endpoint is sent as
the first argument to allow eg. sdk.pub.playersclub.delete accountId.
8. added an entry file lib/goplay-publisher-sdk.rb.

Also changed structure so gem compiles properly for deployment to
rubygems.  Checked this version in for diff, next version will move
files.