create a script for the pyinstaller bundle to apply updates
The launcher.cpp does check if there is a fodler with the name "updates", if it exists will copy all it's contents to the root of the bundle before running bitmask. This part is not ported yet to pyinstaller, and will be needed.
currently, the entry point for the pyinstaller bundles is a bash wrapper that does some fiddling with symlinks and then calls bitmask-app (the main app.py) so maybe the path of less resistance is writing an standalone script under updater/ that does this work, and can be called before app.py.
We have to be careful with it, chiiph mention some problems with the order of files updated in windows. We should have a look on how launcher.cpp does it to get some ideas.
(from redmine: created on 2015-08-04, relates #7304 (closed), relates #5876 (closed))