GiNaC/ginac clifford.cpp indexed.cpp

[Christian Bauer]

Update of /home/cvs/GiNaC/ginac

Modified Files:
	clifford.cpp indexed.cpp 
Log Message:
- added Clifford contractions:
   gamma~mu*gamma~alpha*gamma~beta*gamma.mu
   gamma~mu*gamma~alpha*gamma~beta*gamma~delta*gamma.mu
- detection of free indices of the complete product in
  simplify_indexed_product() could go wrong if contractions resulted in
  composite expressions