Dynamically generate available Primitive Types in ui when loading an existing model

[alec]

When a new primitive type is added to the metamodel all new models created in the GUI support that type, however, all previously created models do not support the new Primitive types. In the loading of an existing model from the GUI the missing primitive types have to be added automatically.

[alec]

References #484: wee need createDefaultTypes else where so changing it to public

→ <<cset 8a0192cd4fda>>

[alec]

References #484: add hooks to postload model

→ <<cset 0991f225b431>>

[Matthias Schoettle]

Resolved with pull request #100 (merged into master).