Grunt v4 upgrade

Minor JSHinting:
- Remove bad "multistring" option
- Add globals for Mocha tests
- Global -> Globals
- Tabs to spaces in rc file to match editorconfig

Mocha:
- Replace dep with grunt-mocha-test
- Mirror options from opts file
- Replace npm test task with grunt

Travis:
- Add missing global installs

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PS: Couldn't see where the "ronn" package was used, but I left it in