declared and installed the attribute RadicalDecomposition

for matrices and modules

+ AMaximalEnvelopingIdeal now uses RadicalDecomposition
  instead of PrimaryDecomposition
renamd AMaximalEnvelopingIdeal -> AMaximalIdealContaining
installed DecideZero for ring elements modulo ideals
added support for IsBound( RP!.AffineDimensionOfIdeal ) and NrColumns( M ) = 1

now we are at least able to compute dimensions of cyclic modules in MAGMA