Fix generation of enums using implicit values

If some or all of the values in an enum are not explicitly numbered, they should count up from the last explicitly numbered value (or from zero if no explicit value was seen yet).
Fix broken unit tests

Some unit tests classes I had at one point got running using IDEA didn't run in the maven build because surefire didn't match them as test classes by class name. These tests got broken. I'll be renaming them in the next commit, but this fixes the tests first so the maven build won't be failing when the class names are corrected.
Rename tests so they are run by surefire