Re-write in ES2015

[Arcanemagus]

Re-write the linter in ES2015, with the following big changes:

• Set lintOnFly to false. This linter is currently only linting the file on disk, not the current contents so this should be false.
• Use helpers.rangeFromLineNumber to generate a range. Since reek only provides a line, it will generate a range highlighting the entire line.

Also includes several smaller changes:

• Move the configuration to a configSchema property in package.json.
• Simplify the parsing, as this was already re-implementing helpers.parse for the most part, just stop using that function entirely.
• Simplify the regex(s) used.
• Handle a race condition where if the editor contents were modified after linting was triggered the markers could be out of place.
• Wrap the debug statements in checks to only show them if Atom is in Dev mode

Fixes #88.

[Arcanemagus]

@dhagerty9009 I split this up a bit so it was obvious what was fixing the existing specs, and what was part of the actual re-write. If you want this focused on just the re-write I can move those off into a separate branch.

[Arcanemagus]

Almost forgot, the new regex can be seen in action here: https://regex101.com/r/99zZs8/1

[Arcanemagus]

@dhagerty9009 I'll be merging this tomorrow morning unless you have something you see needs changing before then 😉.

[Arcanemagus]

Well, tomorrow morning has turned into 4 days later :stuck_out_tongue:, merging this as CI is passing and no feedback has been received for any changes.