Use DOFMapOutput in Jacobian tester

This replaces most of the screen scraping with data from the ```DOFMapOutput```. Except for the _PETSc_ debug output, which still has to be scraped. The use of DOFMap data however enables the Jacobian analyzer to correctly handle block restricted variables and mixed shape functions. Adresses #4182.

I'm working on pinpointing the specific kernels that cause a problem, but that is a combinatoric problem. I need to figure out which kernels to turn on and off to isolate the error while still satisfying the kernel coverage check. This might even not always be possible (or maybe it is, by isolating one kernel, finding out its Jacobian is correct, and then leaving it on..).
Ok, added. Less than 50% of the kernels in tests have documentation and I happened to use one as a template that didn't...