clean up of the branches on the main repository

[keewis]

We have several branches on our main repository that appear to be either out-dated or used to build documentation on RTD (these are no longer necessary since RTD fixed the conda-out-of-memory issues for everyone: building on personal RTD setups should work). Since they already lead to confusion, I think we should try clean them up. Here's a list of the branches I think we can remove:

• 0.11.x: seems to be for the 0.11 releases which are no longer maintained (points to the same commit as the v0.11.3 tag)
• accessor-documentation: I intended to use this for building the documentation on RTD, but I accidentally opened built-in accessor documentation #3988 from it instead of from the branch on my own repository. It will be removed once that PR is merged / closed.
• fix-docs is from more than a year ago. @shoyer, is there anything that was not already merged into master?
• fix-rtd was a attempt to fix RTD when it continuously failed about 1-2 months ago
• revert-3128-drop-keyword-support: I think that was used to give a contributor the possibility to amend to a already merged PR, but in the end a follow-up PR was used instead.
• scipy19-docs and scipy19-docs-backup: these were merged last year (but turns out there are a few pending PRs that try to merge into scipy19-docs)

Edit: I'm going to delete those branches on Monday

[keewis]

I removed all of them except fix-docs, which has 3 commits that are not marked with a PR number. After investigating, I think they are from:

• Print full environment fron conf.py #2709
• Update environment for doc build #2708
• BUG: ensure indexes are reset when coords are modified #2707

so I'll delete fix-docs, too.

[keewis]

now that every branch except accessor-documentation is gone, I'd say this is cleaned up

[max-sixty]

Thanks @keewis ! Tab-completes in git will be easier now!