added Mouse buttons
added state_test
duct tape fix Engine::load_mrb_file
added debug flag to CMakeLists
more work on MoonPlayer
fixed mouse constants in wrong module
more descriptive Mouse Button names
duplicate header inclusion in moon.hxx and engine.hxx
added <sys/stat.h> to moon.hxx
added Input mods
safe engine deletion
lazy patch for segfault on window close
removed debug flag
added pos, seek, length, playing?, stopped? and finished? to Music
modifiers and music
missing file protection for Sound
Simplify Mouse::in_rect?
ALWAYS close the mrb with mrb_close.

What we should do though, is check in init whether mrb was properly
opened, and then terminate on fail.
Sound: throw an exception in the constructor if the object cannot be built.

Zombie objects that are dead, bt still alive are bad.
Call State::render in C++.

Allows us to separate event/update code from rendering code.