This adds a command line option -l (--list-payloads) to list all the
standard payloads available in the 'pyrasite.payloads' package.
It also allows the user to refer to those using just the file name without
a directory, e.g.

    pyrasite $pid dump_stacks.py

It's possible to disambiguate standard payload names from local user files
with the same name by using explicit paths, e.g.

    pyrasite $pid ./dump_stacks.py  # runs user script, not standard payload

- Create a new pyrasite.tests.utils module
- Popen(shell=True) was causing our test suite not to run on ubuntu
- Use a pidfile to know when a program is running, and rm to stop it

This makes it easier to share code within our test modules, while being able to
write imports that work on py2.4 through 3.

Conflicts:
	pkgs/fedora/pyrasite.spec
	pyrasite/__init__.py
	setup.py