Make the front page scrobble/nowplaying artist links use the new URL system

Move Artist url construction to Server
Update profile template to use friendly urls

Change welcome page to use the Server class for getting Now Playing and Scrobbles
Make the Now Playing and Scrobble links use the new getUserURL() function for friendly URLs
Add username to recent scrobbles

Add getURL methods to User and Artist
Create a User object in Auth rather than just passing around the username and userlevel
Make tabs/spaces more consistent