GiNaC/check exam_clifford.cpp Makefile.am exams.cpp exams.h exams.ref

[Christian Bauer]

Update of /home/cvs/GiNaC/check

Modified Files:
	Makefile.am exams.cpp exams.h exams.ref 
Added Files:
	exam_clifford.cpp 
Log Message:
- subs() can be used to substitute functions, tensors and indexed objects
- op(0) of an idx object returns the index value; a nice side-effect of
  this is that idx'es no longer all have the same hash value
- added checks for clifford class