Fix mocks for upcoming rcrunch changes

[gergness]

In an upcoming version of rcrunch, CrunchCube arrays will contain an attribute that identifies what kind of measure type they are so that calculations like prop.table() and bases() can behave correctly on different kinds of measures (rather than assuming everything is a count, as they do now).

This broke one test in crunchtabs because one of the mock fixtures contains CrunchCubes without this new attribute. Fortunately, this change is backwards compatible, so it works with both the current version of rcrunch as well as my still-in-development version.

As discussed, this PR updates that fixture and also records the code I used to update it. I'm not totally sure the generate_mocks script will scale well for generating all mocks, but it's a start. Let me know if you had something else in mind.

[1beb]

@gergness thank you very much. Appreciate the mock generation script as well.