testing: add test for bug SF#2715172
Patch artist: emit warning when kwargs conflict (addresses SF#2848629)
testing: remove previous test images, preventing upload of removed tests
removed empty datetime example from test_axes; now in test_dates
testing: fixup failing jpl unit test infrastructure
testing: add missing file
testing: enable test_dates
testing: convert some JPL units tests to simple nose tests
testing: move baseline images
testing: move test/mplTest/units to lib/matplotlib/testing/jpl_units
