Maintain preset flags

Previously this was just bashing over any flags you passed in.
patch DOMTokenList instead of using a wrapper
remove predeclaration of property and move comment to top
Merge pull request #85 from jakemac53/DOMTokenList

patch DOMTokenList instead of using a wrapper
Merge pull request #58 from jakemac53/master

Maintain preset flags
Make an import without an href properly generate an error event.
Merge pull request #2 from webcomponents/master

update