Merge pull request #3 from HemEM/master

radical ideal and beginnings of primary decomposition
coding style
renamed PolynomialEmbeddingmatrix -> CompanionMatrix
coding style
renamed RadicalForHomalgIdeal -> RadicalOfIdeal

should become RadicalSubobject when code stabizes
correctly declared IsPrimeZeroDim

should be renamed to IsPrimeModule when code stabilizes
correctly declared and installed IsPrimaryZeroDim

should be renamed to IsPrimaryModule when code stabilizes
Installed the function IsPerfect.
Used the new function IsPerfect in IsPrimeZeroDim.
Some coments on IsPrimeZeroDim.

Explains shortly what the algorithm does.
Changed the if request and inserted witness elements.
Some smaller changes in IsPrimeZeroDim

-more local variables
-renamed the minimal polynomials and the squarefree polynomials
-deleted some lines
-used Subset to determine if I = RadicalOfIdeal( I )
Changed IsPrimaryZeroDim.

The ideal takes over the witness elements of the radical, if existent.
Declared and installed PrimaryDecompositionZeroDim.
worked on the last part of IsPrimeZeroDim