Upgrade Grunt to v4

Minor JSHinting:
- Remove bad "multistring" option
- Remove Mocha globals to Grunt since they weren't added to both files
- Tabs to spaces in rc file to match editorconfig
- Enforce the single quoting sytle as per the contributing docs

Mocha:
- Replace dep with grunt-mocha-test
- Mirror options from opts file
- Replace npm test task with grunt
- Strip EOL from version test

Travis:
- Install Grunt and Bower peerDependencies
Merge pull request #90 from nschonni/grunt-v4

Grunt v4 upgrade