separate model and layout data

[shbonita]

The cml file should contain only model data. The layout data for the classes and relationships should be saved in a separate file.

[dtpatrick0706]

The cml is generated by running a srcml2classml script. The cml is connected to the layout using the IDs. -- This comment was written by Bonita.

[ZHarnett]

Along with implementing the separation we want to look into being able to save layout data of diagrams.