feat(core): Use prettier v1, update babel configs

[justingreenberg]

• (deps) updates pretter-eslint to v5+ (prettier v1 engine)
• (feature) use prettier AST formatter for handling semi and single-quotes
• (babel) replace preset-node-module with preset-env
• (babel) use fast-async promise for async/await control flow in node v4 LTS
• (babel) remove unnecessary runtime dependencies (ie regeneratorRuntime)

resolves #3

shouldn't be any breaking changes, could ship a patch release :)

[sheerun]

This PR does much more than updating prettier to 1.0. If you'd like other to introduce other changes I'm open for discussion. For now I'm committing prettier upgrade directly to master. btw. this is a breaking change as shown by changed src/format-files.test.js so major bump is necessary

[sheerun]

Thank you, by the way! :) Feel free to add yourself to contributors list and send another PR

[justingreenberg]

@sheerun cheers dude—happy to see v1 integrated!