Fix gfx_clear bug not using zoom level

There is a strong possibility that i have implemented all zooming code incorrectly. This will require looking at.
Merge pull request #1 from IntelOrca/master

Test pull request
Corrected mistake with zoom_level

Has not been tested. Still requires looking at x, y initial values i think they might be >> as well.
Added extra zoom code

This is some sort of short cut code. I think some of the more common sprites are precomputed for zoomed images.
Re-factored part of gfx_fill_rect

Removed references to global vars that are not required. Possible bug in line 416 will require looking at.
Fixed bug in gfx_fill_rect

As expected _left was incorrect.
Re-factored part of gfx_fill_rect added zooming

Added notes for future work as well.
Re-factor of gfx_fill_rect.

Moved cross_hatching code. Renamed some of the variables to make it easier to follow. Possible future change into big switch statement.
Add Author
Changed layout of gfx_fill_rect

Now in a more logical state. Ready for being reimplemented as a switch with multiple functions.
Re-factor of gfx_transpose_palette

Requires testing i feel as though osinterface call might be incorrect.
Started adding final pattern code

Has not been tested. Looping code not implemented.
Added note about possible issue in draw_sprite.
Fixed compile bugs. Zooming code is broken
Fixed zooming code. Its still not working quite right
Merge pull request #183 from duncanspumpkin/master

More Gfx clean up