Followup to: Filter your tryserver builds, a bit more easily

I made a mistake in not hosting this script from an hg repository; it’s already changed a few times since I originally posted. So, I fixed that. Now one can

hg clone http://hg.mozilla.org/users/cjones_mozilla.com/tryselect
cd $repo
../tryselect/tryselect

Permissions and so forth should be set correctly. (Protip: I symlinked tryselect/tryselect into a directory in my $PATH.)

If you find bugs, please fix them!