integrate work done in https://github.com/cryptoluks/incant

[lnussbaum]

@cryptoluks did interesting changes (mainly introduction of project isolation, and refactoring). Those changes should be looked at and maybe integrated.
@cryptoluks if you are reading this, are you interested in helping with that?

[lnussbaum]

I pushed most of the refactoring ideas, but am still thinking about project-based isolation