Update install docs across PRs, fix issue986

This is my clean-up from merging #42, #44, and #52. After accepting the first two pull requests, I no longer could automerge #52 so I've instead included @achadwick's commits in this PR.

Since issue986 (https://openhatch.org/bugs/issue986) affected the same file, I've also fixed that. This is the removal of the hint for a scrapy problem. It tells the user to use python2.6 which we no longer support.