Need to provide at least one custom model in plugins directory

[butler]

Users would like to see a default example so they can understand the structure. Creating an easy model gives some basics but probably should include a full model from sasmodels including one python only and one python+C. Could take some of the original plugins and convert? should include documentation at beginning and test suite at end so users can start to get used to what will be required to submit as full model.

[butler]

Looks like this will require more "infrastructure" work than just dropping a model into a directory of the repo — at this stage of release best not to muck with it specially since we are documenting how to get there and have the marketplace as well as github to download from. Moving to 4.1

[pkienzle]

Can point users to builtin models for examples.

It would be nice to disable the Advanced Edit/Delete/Load plugin models menu if there are no items in the submenu.

[butler]

We should consider whether this is still necessary - probably more useful to spend time uploading models to the marketplace? Not necessary for 4.2 and not likely to happen so moving