-Add support for raw mouse input in Windows (WM_INPUT messages) when the client cvar mouse_driver is set to 1.
-Add win32inc.h to commonize WIN32 pre-processor defines for Windows platforms.

git-svn-id: http://odamex.net/svn/root/branches/mouse_abs@3846 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Base class's destructor needs to be virtual to ensure child class destructors are executed when deleting a pointer to the base class. Fixes a crash when changing from RawWin32Mouse to SDLMouse.

git-svn-id: http://odamex.net/svn/root/branches/mouse_abs@3847 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Backup pre-existing mouse raw input devices when registering our own for RawWin32Mouse and restore the pre-existing input devices when exiting or changing to a different mouse driver.
-Fixes the issue of broken mouse input after switching from RawWin32Mouse to SDLMouse.

git-svn-id: http://odamex.net/svn/root/branches/mouse_abs@3848 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Add mouse_driver to the Mouse Options menu. The availible options are dependent on the user's operating system.

git-svn-id: http://odamex.net/svn/root/branches/mouse_abs@3849 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Update the event hook for RawWin32Mouse to only examine PM_REMOVE messages rather than duplicated PM_NOREMOVE messages.

git-svn-id: http://odamex.net/svn/root/branches/mouse_abs@3850 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Rework input grabbing when the game window goes in and out of focus.

git-svn-id: http://odamex.net/svn/root/branches/mouse_abs@3851 b0bcef46-2027-0410-bd56-ab726e9a1d04