Fix undefined NULL
change the type of currently undefined list entries from NONE to DEF_CMD
use NULL instead of 0 for pointers (feInitRessources)
fix: WarnS not available
Merge branch 'spielwiese' of github.com:Singular/Sources into spielwiese

Conflicts:
	Singular/misc_ip.cc
Merge branch 'spielwiese' of https://github.com/hannes14/Sources into spielwiese

Conflicts:
	Singular/misc_ip.cc
Merge branch 'spielwiese' of https://github.com/fieker/Sources into spielwiese
memory cleanup
fix problem in mixed size mult by 0
memory cleanup:
  make nInitChar(n_Z, ...) and everything handled by rmodulon.cc
take a copy of the modulus argument.
  Reason: the modulus needs to be deleted in KillChar, but there is no
legal way to free the modulus at this poit. From outside rmodulon, the
modulus is allocaed by omAllocSize (or is on the stack). Within rmodulon
everything is allocated and freed to omAllocBin.
Since they (aparently) cannot be mixed, I take a copy.

Other reason: if the same ring happens to be created twice, the
reference would not have been transfered at all...

Changes to Singular/* to delete the modulus after creation of the ring.