Better default tab behavior

This small patch does two things

1. Allows defaulting to a specific tab using a url like /your/page?qt-QT_ID=TAB_INDEX

2. Currently when the qt block loads, we trigger a click on the users last clicked tab stored in a cookie. This is good, but there are times when you may not want this behavior. This patch adds an option in the config to enable/disable this behavior per qt block (quick_tabs renderer only)