initial commit for event-os, move event outside os
remove OS.cpp
separate definition from implementation in OsEventBuffer
replace os functions with os_event_buffer functions
replace old code according to OsEventBuffer implementation
clear OsEventBuffer at the end of frame()
update android code base according to OsEventBuffer implementation
comment some code
rename OsEventBuffer in EventBuffer
define g_os_event_buffer in OS instead of EventBuffer
move EventBuffer to engine
fix EventBuffer
add events test for EventBuffer's testing
fix read counter in EventBuffer
improve events test