Add "After" attribute.

[nemec]

Conceptually similar to the "Depends" attribute, only it doesn't drag tasks into the execution plan if they're not already in there.

Sample use case:
You have one task that creates file A and a second that copies A to a remote server. When creating and deploying, the second task must always come after the first, but if for some reason you want to re-send A (say you accidentally deleted it on the remote server) but you know the local A still exists, there's no point in rebuilding it. There should be a way to say "run task two" and not have it pull in task one (even though it "depends" on it during normal execution).