pre- and post-apps

[http://orlammd.pip.verisignlabs.com/]

Hi!

It could be cool to be able to define a post-apps, which would run only once all the studio is loaded (something like a script positionning windows, for example).

I'm not sure how this can be handled, as it suggests that ladish has an information about the state of the apps, but anyhow, could be cool.

The opposite (an application which runs before any of the others starts) could useful too.

[http://nedko.arnaudov.name/]

17e02f89a3ea1a9f9679ec7921909cc40c2d70f8 commit message is wrong. It fixes #184, not #183