Unwrap if needed for the reference node of insertBefore
Add work around for Firefox bug related to window methods
Merge pull request #326 from arv/firefox-window-workaround

Add work around for Firefox bug related to window methods
Use FocusEvent for testing for constructable events instead
README: add :host() 1-level nested parentheses limitation. Fixes https://github.com/Polymer/docs/issues/197
Use emulated dispatchEvent for EventTarget.prototype.dispatchEvent
Merge pull request #324 from arv/unwrap-if-needed

Unwrap if needed for the reference node in insertBefore
Merge pull request #329 from arv/event-propagation

Use emulated dispatchEvent for EventTarget.prototype.dispatchEvent
Merge pull request #325 from arv/event-constructors

Use FocusEvent for testing for constructable events instead
new FocusEvent fails in Safari
Merge pull request #330 from arv/focus-event-init-bug

new FocusEvent fails in Safari
Fixes https://github.com/Polymer/ShadowDOM/issues/190
Change GeneratedWrapper to CustomElementConstructor for readability.
add isntanceOf assert
add semi-colons for style.
Merge pull request #331 from sorvell/master

Enhance compatibility with native custom elements
Avoid stack overflow when Element.matches is supported by the browser

In http://crbug.com/326652 support for Element.matches(selectors) was
added to Blink, but it was reverted because it caused tests using
Polymer to start failing due to "Maximum call stack size
exceeded".

The problem is that the Element wrapper unconditionally implements
Element.prototype[matchesName] using this.matches(), which is the same
function if matchesName == "matches". Make the forwarding function
conditional to solve the problem.
Merge pull request #332 from foolip/matches-stackoverflow

Avoid stack overflow when Element.matches is supported by the browser
IE is unhappy if insertBefore has a refNode argument that is undefined so ensure it’s at least null. Partially addresses issue #333
IE does not trim an option.value if it is created with surrounding spaces. Partially fixes issue #333.