Using Ruby 2.1.2. Also replaces the pbkdf2 gem with the openssl gem, because the pbkdf2 gem seems broken on Ruby 2.x.
Fixes a minor bug, which practically only occurs when using the debugger.
Adds API.current_call to get the request path used on the API.
Removes duplicate UnknownObjectException and adds ResourceNotFoundException.
Improves the id_type support. The id should always be a string of hexadecimals. By default the id is interpretated as BSON::ObjectId, but in case of custom keys, the id_type can be set to :binary. In that case the id is interpretated as BSON::Binary.
New version.