Create stubs for all the disabled subsystems

Test all the platforms and drivers

Wish list for the 1.3 development branch:

* Add mousewheel events (new unified event architecture?)

* DirectInput joystick support needs to be implemented

* Be able to enumerate and select available audio and video drivers

* Fullscreen video mode support for MacOS X

* Explicit vertical retrace wait (maybe separate from SDL_Flip?)

* Shaped windows, windows without borders

* Multiple windows, multiple display support

* SDL_INIT_EVENTTHREAD on Windows and MacOS?

* Add a timestamp to events

* Use RDTSC for timer resolution on x86 hardware

* Add audio input API

* Add hardware accelerated scaled blit

* Add hardware accelerated alpha blits

* Redesign blitting architecture to allow blit plugins

In the jump from 1.2 to 1.3, we should change the SDL_Rect members to

int and evaluate all the rest of the datatypes. This is the only place

we should do it though, since the 1.2 series should not break binary

compatibility in this way.

Requests:

* PCM and CDROM volume control (deprecated, but possible)