added retina resolution icons
added sources files
Update description for "sublimelinter_mark_style" setting

The old description did not match the default value.
Updating JSHint to v2.1.2
Updating PEP8 to v1.4.5
Updating PyFlakes to v0.7.2
Merge branch 'retina-gutter-markers' of https://github.com/escusado/SublimeLinter into escusado-retina-gutter-markers

* 'retina-gutter-markers' of https://github.com/escusado/SublimeLinter:
  added sources files
  added retina resolution icons
Cleaning up; no need for 16px images.
Normalizing layers and renaming.
Tweaking icons.
Updating JSHint to v2.1.5
Updating JSLint to latest.
Updating PEP8 to v1.4.6
Updating Pyflakes to v0.7.3
Updating changelog, messages, and version numbers.
Merge branch 'master' of https://github.com/SublimeLinter/SublimeLinter

* 'master' of https://github.com/SublimeLinter/SublimeLinter:
  Updated link to the jshint options documentation