docview: simple pointer usage issues.

The program was overwriting the pointer itself, and not the location
the pointer is pointing too. Simple mistake! :-/
docview: removes commented code we don't use or need any more.
Initial support for reading OS/2 Bitmap files.

They have a slightly different structure to Windows BMP files - now the
more common format.
docview: debug code to help debug reading images from INF files.
docview: Enabled support for reading images from INF files. (WIP)

This is still Work-In-Progress because the images are displayed, but
sometimes incorrectly, or with a wrong color palette. Either way, this
is progress, and very long overdue. ;-)