Build: Fix JSHint Globbing and add .jshintignore

- .min.js files shouldn't be under src/
- Using the .jshintignore allows the CLI JSHint to behave the same as
the Grunt version
Date Polyfill: JSHinting

- Trim trailing whitespace
- Correct XRegExp loading comment and add global
- Hoist multiple var statement
Build: Bump JSHint version
Merge pull request #3374 from nschonni/fix-jshinting

Fix JSHinting