Fix crash on undefined macro + update bin/ccss

1. When the parser encounters an undefined macro, it tried to call the 'fail' function which is not in scope at that point. This results in an unhandled exception being thrown and the program crashes. This has been fixed by raising ParserError directly rather than calling the 'fail' convenience function. While it is possible to define a fail function in that scope, this seems cleaner for now.

2. The bin/ccss script seemed to be an older version as compared to the clevercss/ccss.py script. The bin/ccss script has been made identical to clevercss/ccss.py.