Engines
- CAN_GO_NEXT : mprisdbustypes.h
- CAN_GO_PREV : mprisdbustypes.h
- CAN_HAS_TRACKLIST : mprisdbustypes.h
- CAN_PAUSE : mprisdbustypes.h
- CAN_PLAY : mprisdbustypes.h
- CAN_PROVIDE_METADATA : mprisdbustypes.h
- CAN_SEEK : mprisdbustypes.h
- NO_CAPS : mprisdbustypes.h
- UNKNOWN_CAP : mprisdbustypes.h