added example for SquareFreeFactors
declared, installed and added example for SeparablePart for univariate polynomials over perfect fields.
Created a new gd/gi file: RadicalComputation
Missed these lines in the last commit: Creating RadicalComputation.gd/gi files
declared, installed and added example for RadicalForHomalgIdeal.

Computes the radical of a zerodimensional Ideal,
so far just for rings with perfect coefficient field.
declared, installed and added example for PolynomialEmbeddingmatrix.
(Forgot the special name for this matrix)
Created new files: PrimaryComputation.gd/gi
declared IsPrimeZeroDim and installed the first part of the algorithm.
declared and installed IsPrimaryZeroDim
coding style
removed obsolete declaration of IsIrreducibleHomalgRingElement