Export plug-in interface

[Jean-Francois Arseneau]

Description by jonob:

An incredibly cool feature we should implement are Export plug-ins.

Whenever I mix LUGradio or one of my songs, I will use Cubase to mix down my composition to an MP3 and/or Ogg file. This file is then dumped on my disk. Now, in some cases, you want exactly that (to just stick the file on the disk), but in many cases you need to *do something* with that file. In the case of LUGRadio, we export to a number of different high/low quality files, upload them to a server and trigger a script. In the case of my own music, I export the file, upload it to recreantview.org and create a new page in Wordpress.

It would be incredibly useful to automate this as much as possible. To do this, we should support export plug-ins. You should be able to easily install a plug-in that will export to a particular place. This would not only automate workflow, but make Jokosher very extendable.