GiNaC/ginac clifford.cpp clifford.h color.h

[Christian Bauer]

Update of /home/cvs/GiNaC/ginac

Modified Files:
	clifford.cpp clifford.h color.h 
Log Message:
- added get_representation_label()
- clifford contractions honor repr. label
- first implementation of dirac_trace(), works with 0..3 clifford objects