Extend API to support triggering reloads.

[tohagan]

I'm trying to get this issue working using symlinks that avoid the need to perform PG rebuilds when only HTML/JS/CCS files change.

• Integrate with PG CLI to support custom/3rd party plugins and multiple live devices. phonegap-app-developer#127

I'd like to be able to watch changes on additional symlinked directories since the Gaze watcher lib used in the autoreload middleware does not detect these symlinked changes. I've considered many possible solutions for this and would really like to chat about them with you sometime to arrive at one that works best for the PG team.

My current solution is that I cook up my own version of 'phonegap serve' and watch my own files/folders but this is really just a hack for my specific project & framework (I'm coding Sencha Touch). So I figured that perhaps a quick and simple approach might be to extend the connect-phonegap API to allow triggering reloads.