Refactor Gopt

[PaulWAyers]

@tczorro should we merge the refactor branch into master and use that as the new base branch?

I was looking at Gopt last Thursday with @FarnazH and it's clear we needed a refactor, but that was still the master branch; some of the issues are resolved in the refactor and I think that's what we'd want further development to be based on?

[tczorro]

@PaulWAyers It would be a good idea to use refactor as the new master. I think there are some undone work but it should not be the blocker. Those changes can be made later on. Or we might never get the refactor done