Fixes to XHTML/CSS/JS, plus new scrolling sidebar and favicon

XHTML:
* Added scrolling to sidebar nav.
* Added copyright (license) statement as a modal activated by clicking a link at bottom of sidebar.
* Created favicon.  Alternative (favicon-connect.ico) also available in resources/images folder.
* Expanded page titles.
* Miscellaneous HTML tweaks.

CSS:
* Added related styles for scrolling sidebar.
* Numerous adjustments to fix appearances.
* Fixed missing brackets in @media rules.
* Removed old, unused styles.

JS:
* Applied fix to Tablesorter JS (jquery.tablesorter.min.js) because of incompatibility with xhtml.
* Cleaned up page functions JS, moved to separate file (admingui.js).