[Detail] Tiny renaming.
[KQueue] First look.
[Detail] Some minor cleanup.
[Detail] Temporary switching on native library developing.
[Detail] Extending interface. More implementation.
[Detail] Printing via special printable structure.
[Detail] Also trigger user event.
[Detail] Some planning added.
[Unit Testing] Fixed accidentally broken test.
[Detail] Thread safety for kqueue.
[Code Clean] Dead code elimination.
[Code Clean] Warning fix.
[Unit Testing] Test for single file watch & remove.
[Detail] Tiny renaming.

Renamed kevent function that creates invalid event.
[Refactoring] More convenient API.

KEvent lightweight wrapper now provides three initialization functions:
 - Direct mapping to the syscall - raw.
 - Event initialization without data being attached - new.
 - Invalid event placeholder - invalid.
[Code Clean] Fix some warnings.
[Detail] More events.
[Detail] Some planning.
[Detail] More planning.
[Detail] Finished planning.