When Automatically resize window is set:
1. Fixes#1640 which was caused by mixing screen and working area
coordinates
2. Moves window up and left to try and fit it in the working area
3. Adds option to maximize the editor window when it is larger than
working area (such as when capturing full desktop or multi-monitor).
Adds setting to allow user to save the last drawing mode used in Greenshot
so that it will be selected next time image editor is opened.
Also adds setting to config file to allow user to change the default
drawing mode.
Closes#1609
