Merge pull request #634 from YueRen/gcd_fixes

fix: gcd over integers of two terms ignoring coefficients
singular_4_1: report version 4100
Groebner Walk, Sagbi Walk
bug fixes for walk stuff
format errors
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.)
memory leak in ASSUME (from master)
memory leak in Eval (from master)
debug: allow ring tracking via omalloc
memory leak while redefining ring-dep lists
code cleanup: types in lib, comments
removed Short/bug_554 from Short/ok_s.lst
fix: listvar for rings in non-actiive packages
fixed: typo in alias stuff
fix: dangling else in updateResult (if cf is not a field)
newstruct: setting basering of ring-dep stuff
minor optim. for return(..)
introduce nCopyCoeff for copying coeffs
add a tool for testing: creating custom random ideal generators
exit on warning