Make parsing smarter, e.g. don't match `xit` in `exit`.

Current `ddescribe-iit` parsing is way too simple, it even matches things like `'exit'` somewhere inside the code as invalid since it contains the `xit` substring. I made it smarter.

Commit summary:
1) Make parsing smarter, e.g. don't match `xit` in `exit`.
2) Corrected `grunt jshint` output, created a separate jshint target for tests/
3) Added .gitignore & .gitattributes.

I put it in 3 different commits since it makes sence semantically but merge it however you want.