show progress during opencl test

[pkienzle]

The tests run by the OpenCL config dialog can take a long time to run the first time, before any of the DLLs are compiled. The user needs to see that the tests are in progress, and ideally know how much longer the tests will take.

When running unit tests in verbose mode from the command line, each test is displayed as it is completed. The result is:

$ python -m sasmodels.model_test -v all
test_adsorbed_layer_python (__main__.ModelTestCase) ... ok
test_barbell_dll (__main__.ModelTestCase) ... ok
test_barbell_opencl (__main__.ModelTestCase) ... /usr/lib/python2.7/dist-packages/pyopencl/__init__.py:61: CompilerWarning: Non-empty compiler output encountered. Set the environment variable PYOPENCL_COMPILER_OUTPUT=1 to see more.
  "to see more.", CompilerWarning)
ok
test_bcc_paracrystal_dll (__main__.ModelTestCase) ... ok
test_bcc_paracrystal_opencl (__main__.ModelTestCase) ... ok
test_be_polyelectrolyte_python (__main__.ModelTestCase) ... ok
...

A dialog showing the test currently running and a progress bar showing k tests out of a total of n would give the user the feedback that they need. A cancel button would also be nice.

[pkienzle]

Compiling the DLLs in parallel would speed up the test. Maybe update sasmodels.core.precompile_dlls to operate with multiple threads, and call it before running the tests.

It may also be possible to precompile the OpenCL in parallel in advance, but this may depend on the particular driver.

[krzywon]

The Qt GUI console captures the stdout, so this is already solved there. Whether or not we want to put it into wx is a matter for debate.