Bakge.h: Fix missing _DEBUG flag in non-release builds
gdk/engine: Remove Bindings files

Lua bindings will be part of the library in v0.2.0
win32_Mutex: using Critical Section member
win32_Mutex: using Critical Section on *tors
win32_Mutex: using Critical Section in Create()
win32_Mutex: using Critical Section in Lock()
win32_Mutex: using Critical Section in Unlock()
win32_Mutex: TryLock() declaration
win32_Mutex: TryLock() implementation
win32_Mutex: use CRITICAL_SECTION object instead of LPCRITICAL_SECTION
win32_Mutex: use address of CRITICAL_SECTION in api