* Add comments showing parser arguments
Since this is how they are invoked, the comments make it easier to maintain.
* Use babylon.parseExpression for JSON
See https://github.com/prettier/prettier/issues/2378#issuecomment-314600778
Note that this doesn't yet print comments:
echo '{/*comment*/"K":"V"}' | ./bin/prettier.js --parser json
* Remove parser-json.js
This reduces duplicate code in the built package.
See https://github.com/prettier/prettier/pull/2476#pullrequestreview-50181398
* Add test with block comment in JSON
* Fix test with block comment in JSON
* Add test with line comment in JSON
* Don't build now-redundant parser-json.js