Revert "Groebner Walk, Sagbi Walk"

This reverts commit ffd4a9600207a9670cfe0cb81450accbaaec26d7.

Conflicts:
	Singular/LIB/modwalk.lib
	Singular/LIB/rwalk.lib
	Singular/LIB/swalk.lib
	Singular/walk.cc
	Singular/walk.h

To many bugs: - syntax error (mainly: include paths)
              - changed interface without changed libs (grwalk.lib)
	      - several failing tests (in Manual/*, Buch/*, etc.)