Rewrite in ES2017

[Arcanemagus]

Rewrite the linter in ES2017 code, including the following changes:

• Use Helpers.rangeFromLineNumber() to generate ranges for incomplete positions, this will use the regex for the current language to highlight the next "word" automatically.
• Move to the Performance API for measuring time. Times are only logged to the console in Developer mode now.
• Move the setting to a configSchema in the package.json so Atom doesn't have to execute the code to read the settings.
• Utilize async/await where possible

[Arcanemagus]

@maxjacobson You'll probably want to fix the Code Climate config, as I only know enough to cut out the coffeelint part 😛.

[maxjacobson]

Happy to re-enable eslint after this is merged

[Arcanemagus]

Whoops, looks like this got dropped. Looking into finishing this up.

[Arcanemagus]

There we go, passing build!