0.24 release

For some reason the one on PYPI was 0.23 (?) so I skip a couple of
versions.
memory_usage accepts Popen as argument

The "proc" argument of memory_usage() can now be a subprocess.Popen
object.
Added mem_profile executable

mem_profile allows both launching and monitoring a process.
timeout parameter works for Popen process

In memory_usage(), when passing proc as a Popen object, the timeout
parameter is now properly handled.

Updated memory_usage documentation.
Renamed mem_profile to mprofile

Output file now contains a timestamp.

setup.py now properly installs the mprofile executable.