Add ESLint reporter

[dciccale]

Add option to specify an .eslintrc file instead of jshint.

plato -d report -e .eslintrc file.js

[jsoverson]

Thanks for taking the time to do this. There are some lint errors and the eslintrc is actually parsed as yaml so there are some issues that need to be addressed, but if the reporter is accurate then this merge will be used as a springboard to get eslint support in.

[baer]

@jsoverson Looks like this would close out #78

[taybin]

Any progress on this?