[WIP] polyfill-version

[lukasoppermann]

Instead of making the library ie compatible, maybe we can just include polyfills for the stuff that IE11 does not support, instead of having extra functions.

• import all polyfills into a polyfill file
• add to readme
• element.remove
• element.matches

This will also make it easier to clean the code base once IE11 can be dropped. Also it could fix #300 in the current version with just a minor instead of a major version increase. This also fixes #342

[coveralls]

Coverage increased (+0.2%) to 81.657% when pulling 3f968ec on polyfill into 30052a6 on master.