Command line points of entry

Instead of specifying code, we specify name of the script and arguments to pass to it. Pythoscope will:
 - fake __name__ to be "__main__" (see http://groups.google.com/group/comp.lang.python/msg/705c1017b5f138e9)
 - inject args into sys.argv
 - intercept system exit and report it differently than other exceptions

Those of points of entry will be stored in .pythoscope/points-of-entry/, just like the others, but with different extension (to be decided).