Automatically compile Python scripts when adding to PAK

[Jrius]

When editing PAK files, PlasmaShop 2.x allowed selecting uncompiled Python scripts and compiled them on-the-fly before adding them to the pak. This was slightly more convenient than having to compile those manually.

Back in version 2.x, this required specifying the path to the Python 2.2/2.3 executables in the options dialog. Maybe those could be embedded in modern PlasmaShop somehow to make it even more convenient.