Fixed XML wrapping tags

Updated htc-document tags in accordance with Microsoft guide:
http://msdn.microsoft.com/en-us/subscriptions/ms532146(v=vs.85).aspx#HTC
Even though <public:component> is optional, the xml document without closing tag can be parsed with unexpected results. In my test case the script was ignored completely (no behavior applied to elements).
Adding these changes helped me to fix the issue.