Failing on lint errors when doing a regular build

[rorticus]

Type: feature

The following has been addressed in the PR:

• [x] There is a related issue
• [x] All code matches the style guide
• [x] Unit or Functional tests are included in the PR

Description:

This PR will make the webpack build fail (right away) if there are tslint problems when doing a regular (dojo build) build. If you use watch (-w) or tests (-t) the lint errors will only generate warnings.

Resolves #207