Deleted RestrictedGeneralizedMorphismCategory

and installed new IsWellDefined method for GeneralizedMorphisms
Deleted ToDo-management from GeneralizedMorphismCategory
IdentityMorphism in GeneralizedMorphismCategory
Renamed: AssociatedMorphism -> MorphismAid

because the associated morphism is part of the triple
(domain, associated morphism, codomain)
and not part of the triple
(source aid, morphism aid, range aid).
GeneralizedMorphismFromFactorToSubObject

now based on ImageEmbedding and CoastrictionToImage
instead of MonoEpiFactorization
Started deduction system category.
Started deduction system.
Constructors for deduction system.
View and display
Bugfix: Wrong variable in constructor
Eval and some add methods for deduction system.
Adds for deduction system.
Some bugfixes, first example for deduction system.