Rethinking Standalone installation

Now that pip installs nearly all the dependencies so easily (not pyo sound, and wx/qt depends on Python version) I feel like we could change the standalone installer to be more of a “network installer” resulting in a more “standard” python installation (maybe a separate installation location, like Applications/PsychoPy/ but otherwise a standard python install.

I created an issue on github - let’s discuss the guts there rather than here - but feel free to add minor comments here too.