2014-06-02 More Windowing Progress

Good progress today, fixed a lot of the smaller bugs which were obvious from the last couple of days, and also got two big blocks of functionality into the VGA driver to make things better.

One of the things I'll call a "small bug" is that I've thrown some hacky code in to the current keyboard handler to gather the key up and key down events for the important keys and push them into the window manager, which then adds the events into the event queue for the "active" window.  Because I can't currently select the "active" window, I have added a pointer to the "last opened window" (effectively the tail of the window list) to mimic this for now.  I've removed the test code which pushed input events into new windows, and Doom is actually now playable.

Completed:
- Added the ability to blit bitmap objects onto the screen via the VGA driver.  This means Doom is a lot faster again and has dithering back.
- Added an efficient DrawLine() function to the VGA driver.  This greatly speeds up the window drawing.
- Fixed the KeyUp and Keydown events being reversed.
- Fixed the window title text being drawn in the wrong place.
- Added backspace handling to the window console mode.

Next steps:
- Fix the console scrolling.
- Identify the bug in the keyboard handling.
- Get all drawing routines to use the back buffer to re-enable double-buffering.
- Add the masking support to the Plot8() function (Doom left border problem)
- Identify why the Mode 12h code doesn't work on the Netbook.
- Investigate sound.