Detect tag.hbs template in themes

closes #2320
- changed detection from "tag" to "tag.hbs" in "frontend.js" contrroller
Add test for tag.hbs template.

refs #2321
Merge pull request #1 from halfdan/add-test-tag

Add test for tag.hbs template.
Fixing CodeMirror paths in GruntFile.js
Merge pull request #2321 from polygonix/2320-detect-tag-hbs