increased version
removed obsolete declarations for Zero and One
one more hack in HomalgMatrix for SingularForHomalg

at some point we must rewrite the matrix constructor
of the homalg project to comply with Max' IsMatrixObj
slight change in MinusOne
internal rings now look for RP!.{Zero,One,MinusOne} first

installed corresponding methods
support RP!.AreEqualMatrices for internal matrices
declared and installed ExportRationalParameters and ExportVariables

SetRingProperties for
- IsFreePolynomialRing
- IsWeylRing
- IsExteriorRing
now extracts the rational parameters from the coefficients ring
after RP!.ReducedBasisOfRowModule/ColumnModule we check if the result is equal to the input

in this case we return the input matrix as we might know more about it
(and to save memory)
added caching to GetColumnIndependentUnitPositions/GetRowIndependentUnitPositions

(HomalgExternalCallCounter dropped by one in Purity.g)
added support for PartiallyReducedBasisOfRowModule/ColumnModule

to be used in the methods for the attributes
- ReducedBasisOfRowModule
- ReducedBasisOfColumnModule
(this allows using Singular's mstd and MAGMA's MinimalBasis routine)