autoconf based setup

[teuben]

We do need some kind of "setup". Be it some kind of "python setup.py" or an autoconf based "configure". This is likely related to the issue on hardcoded paths, for one.

[teuben]

There is still the nagging question how this setup is added to your casa session. Ideally it is some code snippet (the execfile) that is added to the ~/.casa/startup.py (for casa6) and/or ~/.casa/init.py (for casa5). This way the routines are available each time casa is started.

[teuben]

I've committed the configure based setup, but it's not clear yet how we separate problems (M100, GMC, ...) vs. path

[teuben]

I tried a new option --with-s4p-problem=PROBLEM but not sure if it will survive