Misc OSX porting things:

• autostart the assistant on OSX, using launchd done
• icon to start webapp done
• use FSEvents to detect file changes (better than kqueue) done
• Use OSX's "network reachability functionality" to detect when on a network http://developer.apple.com/library/mac/#documentation/Networking/Conceptual/SystemConfigFrameworks/SC_Intro/SC_Intro.html#//apple_ref/doc/uid/TP40001065

Bugs: