Made the profile module optional, removing the dependency on the Python development packages.
This was in response to Tiago Pais's <tpais att itqb dot unl dot pt> message at
https://mail.gna.org/public/relax-users/2009-08/msg00040.html (Message-id:
<A3A9E765436240CDA75B3045C405BED6@...>).