declared IsElementOfGrothendieckGroup

as a super filter for IsElementOfGrothendieckGroupOfProjectiveSpace
ChernPolynomial( P, h ) now Assert( 0, IsIntegral( P ) );
FittingIdeal now caches the results in M rather than PresentationMorphism( M )

+ more general filters for NumberOfFirstNonZeroFittingIdeal
ReducedBasisOfModule now supports the option "COMPUTE_SMALLER_BASIS"

PresentationMorphism now calls ReducedBasisOfModule with
"COMPUTE_SMALLER_BASIS" instead of "COMPUTE_BASIS"

(this is motivated by computations over residue class ring,
 e.g., of Rank, which triggers FittingIdeal, which triggers
 PresentationMorphism)
Added ToDoLists.