Change meta model, for datatypes

[alec]

in order to create datatypes, we must change the meta model in two major ways * add a default flag of false to the classifier, to indicate if a class actually a data type

[Matthias Schoettle]

References #485: Improves code and comments.

Removes duplicate code. Removes unused classes/interfaces. Improves RamModelUtils.getTypeBy... methods to make use of RAMInterfaceUtil. Also, fixes problems with use of wrong methods (getAttributeType instead of getTypeByName).

→ <<cset 0d65c8eb7818>>

[Matthias Schoettle]

References #485: Ensures that the datatype property is copied during weaving.

→ <<cset 4f7e6a27e7c7>>

[Matthias Schoettle]

References #485: Adds datatypes as valid types for attributes for the typeDefined constraint.

→ <<cset f2235cb34f70>>

[Matthias Schoettle]

References #485: Fixes the handling of simple array types when finding it by name.

→ <<cset 5517d8e9b1fb>>

[Matthias Schoettle]

References #485: Disallows inheritance and association creation for datatypes.

→ <<cset 81991d2eb70e>>

[Matthias Schoettle]

Merged into master in pull request #103.