* Remove whitespace generation and rely on default printing
Changes to printing:
* Add newline after last empty SwitchCase
* Add newlines around block comments if they are non-flow comments or contain newlines
* Fix a few more fixtures
This has been a feature in Flow for a long time (couldn't easily find a
specific commit adding this). Interfaces are basically undocumented, though, so
it's easy to see how this was missed.
