* Mark transpiled JSX elements as pure
* Avoid duble annotation
* Add "pure" option to the React preset
* Fix generator indentation
* Update tests
* Add tests for the "pure" option
* Update windows fixtures
* 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