* Added LoadingTaskPreferenceActivity for a PreferenceActivity that
displays a loading dialog.
* Because of the way Java inheritence is designed and the structure of
Android Activity code, there was no way to enforce that a
LoadingTaskActivity is passed to LoadingTask on the constructor, while
also working with LoadingTaskPreferenceActivity... So I limited the
constructor to "Activity" and now do a runtime check.. and throw an
exception if the activity does not implement
AbstractLoadingTaskActivity.
* Switched YouTube desktop site over to https URL, and force-accept SSL
certificate on <= Android 2.1 devices (otherwise those devices will not
accept the certificate and the site won't load)