#130 - Updating engine and version file locations. Also updated gemspec.
#130 - oauth/engine.rb - starting point of rails engine.
* Previously all the startup setup was done through init.rb, which is loaded on startup.
* Code from old oauth2_provider init.rb is moved to lib/oauth2/engine.rb. This is a rails engine's starting point.
#130 - Moving generators from old oauth2_provider to new oauth2_provider.
#130 - Moving config/routes.rb from old oauth2_provider to new oauth2_provider.
#130 - Changing routes to new Rails 4 format.