This commit adds module elements as degrees

Squashed commit of the following:

commit 75c559c0ddb7bcb70426554999b1a11e1dcc1feb
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Thu Nov 3 20:03:50 2011 +0100

    Matrices can handle module elements now.

    The methods for creating random matrices over graded rings
    were changed to handle module elements.

commit 8625fe629be8687d597687fcb77f1872222e3e4a
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Thu Nov 3 14:51:31 2011 +0100

    removed obsolete NonTrivialDegreePerRow/ColumnWithRow/ColDegreesFunction

commit 4ff19804833641036da54328d9a650152308f7de
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Tue Oct 25 13:35:45 2011 +0200

    changes in matrix methods applied

    all methods that work with degrees of entries of
    matrices are changed to work with module elements
    instead of intlists. The example Purity.g from
    GradedModules now terminates, but there might be some
    errors left.

commit 12064dced961e530182c106b705db3987ee56614
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Tue Oct 25 10:08:23 2011 +0200

    there is still a problem with Purity

    Purity wants to call a method which seems to be
    not implemented.

commit 2cc61e79eebdb330e3303e8cf925826070239ba7
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Mon Oct 24 23:00:37 2011 +0200

    issue during handling degrees being an integer

    at the moment, there is a problem when getting back an integer from
    time to time; maybe a better way to solve this is to let all the degreefuncs
    return integers by default.

commit c2946343efa428efd92e532295d641716ee76638
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Mon Oct 24 18:04:05 2011 +0200

    degree methods for matrices changed

    now you can get the degrees of matrices

commit 0ea3862b6bdcd1f86777eef8be21af9b974c802f
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Thu Oct 20 10:36:20 2011 +0200

    Added some comment.

    There seem to be some not used functions in LIGrRNG,
    such as NonTrivialDegreePerRowFunction.

commit 41c4991849c62356989b0257cad5492130191f1b
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Thu Oct 20 10:11:12 2011 +0200

    DegreesOfEntriesFunction changed

    The Method DegreesOfEntriesFunction
    has now the same porperties as
    DegreeOfRingElementFunction and is able
    to handle module elements as degrees.

commit a3a2e7aa2d4f4c199e71f0f43245741bdbf533d4
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Tue Sep 20 11:26:28 2011 +0200

    M2 MatrixOfWeightsOfIndeterminates method changed

commit 0be5049ecefebbd4e6866df9eb3ae54e588f7530
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Wed Sep 14 11:19:42 2011 +0200

    DegreeOfRingElementFunction changed. It now makes a difference if
    the DegreeGroup is of rank one or not, so if you can identify it with the integers or not.
    There is a Testfile SebasElemGradTest.g added

commit 922075236ab7279913b5c25d4faa515a7606da3d
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Mon Sep 12 14:54:49 2011 +0200

    Arbeitscommit, Listen werden noch nicht in Modulelemente umgewandelt

commit c0560857b66190c48f07d954626404209f45c90c
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Tue Aug 16 11:52:33 2011 +0200

    Method WOI changed for Extorior Algebras, but not tested yet

commit 9212fd0af0304d048ef561636876e75c9085e0c7
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Sun Aug 14 22:29:11 2011 +0200

    DregreeGroup von BaseRing wird nicht richtig gesetzt, Version ist so nicht Lauffähig falls GraduierungsModul dim >= 1 besitzt

commit 02fd46529e633747222e63af3333845576b7178b
Author: Sebastian Gutsche <gutsche@momo.math.rwth-aachen.de>
Date:   Fri Aug 5 16:04:45 2011 +0200

    Z als freier Modul eingefuegt
Setters for WeightsOfIndets added.

Now WeightsOfIndeterminates is no longer a
Attribute but a method. There were setters and getters added.
Changed the header of a method.

dont know why it was not like this
in the first place
Changed some errors that caused inconsistent

output in the matrix degree methods.
Added some changes for multigrading.
Fixed an error in RandomMatrix . . .
Added some more multigrading methods.
Improved constructing of degrees.
Light improvements of methods.
Merge branch 'devel' into test_master

* devel:
  Light improvements of methods.
  Improved constructing of degrees.
  Added some more multigrading methods.
  Fixed an error in RandomMatrix . . .
  Added some changes for multigrading.
  Changed some errors that caused inconsistent
  Changed the header of a method.
  Setters for WeightsOfIndets added.
  This commit adds module elements as degrees

Conflicts:
	PackageInfo.g
Changed Degree-setters.
Slight improvements to deg_funcs
Made slight performance improvements.
Fixed a stupid error in DegreesOfEntriesFunction.
Changed WeakPointers to Pointers

for degrees of matrices.
rename zero_elm -> zero in DegreesOfEntriesFunction
predefine weights in NonTrivialDegreePerColumnWithRowPositionFunction
fixed bug in NonTrivialDegreePerRowWithColPositionFunction

by removing the local declaration of zero
Merge branch 'devel' into gutsche

* devel:
  installed RingOfDerivations for [ IsHomalgGradedRingRep ]
  modified the tool method Diff

Conflicts:
	PackageInfo.g
	gap/GradedRing.gi