support PyInstaller as bundler Tested with PyInstaller 3.2.1, resulting exes can run `wflow_rhine_sbm_nc` example without errors. Also all executables can start without crashing (unless they do because of missing command line arguments).
If UPX is available, compression will be applied. Even with compression the size of the final dist folder is currently around 280 MB. This can possibly be reduced by looking at what [excludes](http://pyinstaller.readthedocs.io/en/stable/spec-files.html) are possible to add.