SoCoUPnPException (#14) and fixed "socos" script

This builds upon #14 and fixes problems with the "socos" commandline script.

As distutil's ``entry_points`` parameter [creates the executable script automatically](http://pythonhosted.org/setuptools/setuptools.html#automatic-script-creation), it's not necessary to have a file named ``socos`` in the source. I've therefore moved ``bin/socos`` back to ``socos/runner.py`` as previously suggested by @petteraas. On installation distutils will automatically create a ``bin/socos`` with something like

```` python
#!/home/stefan/socos/venv3/bin/python3                                          
# EASY-INSTALL-ENTRY-SCRIPT: 'socos==0.1','console_scripts','socos'             
__requires__ = 'socos==0.1'                                                     
import sys                                                                      
from pkg_resources import load_entry_point                                      
                                                                                
if __name__ == '__main__':                                                      
    sys.exit(                                                                   
        load_entry_point('socos==0.1', 'console_scripts', 'socos')()            
    )                                                                           
````