Auto-correct in space-related cops

This has taken a rather long time, but here it is now. There were a lot of problems with conflicts between different corrections that I found by auto-correcting a fairly large number of gems. I have fixed those problems in https://github.com/jonas054/rubocop/commit/310dc42f78be03d3c5214b825ea815a903a4c528 but have not come up with a silver bullet for all similar cases.

Fixes #553.