ZBitmap

Copperbox revision 500!

Writing bmp files is re-enabled, though there is a bug where the output bitmap isn't the same as the input bitmap. As ZBitmap doesn't do any translation it should be. It does seem to work okay for 24 bit colour, but not for other ones.

Also this is just writing bmp files. There is no code yet to enable writing an arbitrary buffer containing bitmap data to a bmp file, which is really the most important bit.