Renamed buttons to default names and added load image button.
Moved draw_ruler function out of signal handler class.
Console automatically scrolls to last line, and no longer collapses as the GTK Expander widget behaved badly.
First steps towards loading and viewing pdf files
Added file open dialog and moved draw_ruler to seperate file
Moved image rendering code to its own method
Added device dimension options, fixed ruler scaling, changed conflicting length keyword in drawruler.py
Draw correct device dimension box
Made preview window scrollable