have assert capture the filename a test was defined in

[kellyredding]

It would be nice to have so you can write an assert-view that shows results by file.

[kellyredding]

Thoughts so far:

• at Context inherited time * store off the inheriting class as the loading_context_class on Assert.suite * store off the last caller as the loading_caller on Assert.suite.loading_context_class
• add a hook for 'method_added' * if a local_public_test_method * store off Assert.suite.loading_context_class.loading_caller as an instance variable on the method just added
• at Suite prep time * for each local_public_test_method * pull off the loading_caller ivar on the method and associate with the test created

Eh, this is neat, but seems a little complex.