Fixes for header, footer, and jQuery 

Fixes issues related to/noticed when testing the header, footer, and jQuery update.

*Make it so you can access drop down menus even from the current page (aka remove span_if_current from primary links; most noticeable with Hi, username! menu)
*Remove styles from the old footer that were causing the new one to display incorrectly in IE8 and lower
*Change the Volunteer link text under About to Donate or Volunteer
*Change the Tag Wrangling link in Hi, username! to point to the user's tag wrangling home
*Add Invite Users link to the admin header
*Set a maxwidth on the search tooltip to prevent horizontal scrolling in Firefox
*Fix some broken HTML on the invite requests page that was causing display issues in Opera
*Reorder the navigation buttons on the various search pages so they are in the same order as the links in the search drop down menu
*Fix scrollTo for pagination of AJAX comment pages and move scrollTo-related JavaScript to the commentable partial, since it is only used in that location
*Add Get Invite link to the Log In menu
*Change CSS for drop down menu background so the drop down menus have background colors when images are disabled in Opera
*Shrink site logo image so it displays nicer on Windows and tweak mobile stylesheet so the new image displays correctly there
*Add menuitem role to drop down menu items to better adhere to ARIA standards
*Move the JavaScript for the drop down menus up so it loads earlier
*Stop loading qTip JavaScript on every page, since it already loads on the tag set nominations page where it is needed
*Stop including the LiveValidation JavaScript in the _javascripts partial, since it's already in the page head and loading it twice means it doesn't work