Deleting stale branches in extensions

[tedinski]

We should probably have some scripts for helping manage dealing with all the extensions.

Unless I'm mistaken, feature/env and feature/type_qualifiers are all stale? It'd be nice to have a script to mass-delete these (including from github), in particular so the Jenkins All Branches view is not so polluted: http://coldpress.cs.umn.edu:8080/view/All%20branches/

[krame505]

Sounds like something that belongs here: https://github.com/melt-umn/ableC-vm-artifact
You could probably just modify https://github.com/melt-umn/ableC-vm-artifact/blob/master/checkout-branch.sh