We can remove the function in MtNativeActivity now
as it serves precisely that purpose: to tell irrlicht
that we handled the esc key.
TODO for later:
* Perhaps try to find a more performant container than KeyList
- Add warning log level
- Change debug_log_level setting to enumeration string
- Map Irrlicht log events to MT log events
- Encapsulate log_* functions and global variables into a class, Logger
- Unify dstream with standard logging mechanism
- Unify core.debug() with standard core.log() script API