Add options to load only certain elements (or extra elements specified by the user)
- Now dealing with duplicate images (They only trigger an event once)
- Added a quick polyfill for IE < 9 that doesn't have Object.keys
- Regex matching now deals with multiple backgrounds properly.
Small bug fixes + fix type
Fix test suite page + first tests
Small bug fix to exit when there is nothing to load
Update test suite with more test cases.