WIP: Fix position when opening multiple bitmaps

Problem: if y-axis pointing up and a inkscape window is already open, opening (not importing) new images load a bitmap that is displaced from the canvas.

The problem is that the patched functions use SP_ACTIVE_DESKTOP, which is wrong (the desktop corresponds with the already open document).

This is a pretty clunky solution that simple makes sure the behaviour is the same as when an inkscape window is not open yet (i.e. first image when starting from the terminal inkscape image.png).

Fixes #337 (closed) Edit: correct this to autoclose on merge