updated theory to support running with a URL prefix for use behind a web proxy.

[neoice]

modified:   development.ini
modified:   server.ini
modified:   theory/controllers/main.py
modified:   theory/model/albumart.py
modified:   theory/public/css/fullscreen.css
modified:   theory/public/css/styles.css
modified:   theory/public/css/ui.slider.css
modified:   theory/public/js/theory.js
modified:   theory/templates/albums.html
modified:   theory/templates/fullscreen.html
modified:   theory/templates/genres.html
modified:   theory/templates/index.html
modified:   theory/templates/letters.html
modified:   theory/templates/playlist.html
modified:   theory/templates/stats.html
modified:   theory/templates/tracks.html

[ralfonso]

Thanks!