A few spec compliance changes to pass the w3c tests

- relatedTarget must be null if pointerevent is capturing
- `new PointerEvent(..) instanceof PointerEvent === true`
- Manual tests: http://github.com/w3c/web-platform-tests
Merge pull request #105 from azakus/web-platform-tests

A few spec compliance changes to pass the w3c tests
Allow for use in old IE by providing a non-getter API for size of pointermap
Update everything that can't be polyfilled in old IE.

Replace PointerMap.size getter with a size method.
Quote properties named delete.
Added support for external hooks for event binding and dispatching.
Merge pull request #106 from scottgonzalez/old-ie-support

Old IE support