Rewrite attachandrun in python

[achernya]

attachandrun.c is a horrible bit of C that tries to do things that are like subprocess.open(). To make matters worse, it links against libathdir, for no good reason, when you can just do athdir locker -t bin to get the same effect, and the code already does fork.

Instead of keeping it around, just move to Python, as this will be shorter, and prettier.

[achernya]

Here's the rewrite  for review. Please send me comments before I commit it; the current plan is to integrate attachandrun, athrun, and gathrun into the same source package.

[achernya]

Committed in r25974.

[jdreed]

Didn't this go out already?