+ metadata is now a class method because this way we save memory when checking for proper bundles in the PluginController
+ changed the DataSourceProtocol accordingly
+ fixed typo of “Kranken” that meant to be “Kraken” in the AIKrakenExchangeController
- removed any MtGoxAPI references
+ added dataSource as plugin interface
+ load bundles and check for DataSourceProtocol is now completely in availableBundles
- removed unneeded methods
+ loadBundleAsPlugin:path for setting the plugin to use (for future consideration: maybe return an instance of the bundle and let the receiver (DataController) do the rest instead of managing the plugin all by itself in the PluginController)
+ now checking for + metadata support in classes
changed  metadata to class method