cosmetics
Reduce variable scope.
remove unneeded variable
Enable C4701 for /W3.
MainFrm.cpp: remove unused variables.
VobSubFile.cpp: break after return doesn't make sense.
DX9SubPic.cpp: fix possible NULL pointer dereference.
Fix using potentially uninitialized local variable.
Avoid variable shadowing.
DX9RenderingEngine.cpp: Fix leaking memory due to an exception.
Use unsigned short instead of int in a few places that makes sense to do so.
Remove unneeded typedef.
Be consistent with function's variables.