minimap scrollbar: Refactor the pixmap creation code.
minimap scrollbar: Refactor the pixmap creation code.

Give sensible names to the variables, add comments, rearrange stuff...

hlamer/kate,hlamer/kate,hlamer/kate,sandsmark/kate,DickJ/kate,sandsmark/kate,hlamer/kate,sandsmark/kate,DickJ/kate,sandsmark/kate,DickJ/kate,hlamer/kate,hlamer/kate,jfmcarreira/kate,cmacq2/kate,hlamer/kate,hlamer/kate,jfmcarreira/kate,hlamer/kate,hlamer/kate,DickJ/kate,cmacq2/kate,jfmcarreira/kate,cmacq2/kate