Part of an effort to generally improve unit tests and test data usage in some of our repositories (gmprocess, shakemap, strec, etc.)

The goals are to:

• Reduce redundant data by allocating it with fixtures that can be reused in tests
• Control test state more carefully to prevent flaky tests that fail due to problems with setup/teardown using things like shutil
• Possibly compartmentalize testing & data on something like a module-by-module basis to facilitate optional levels of installation in packages like shakemap and strec