relax SVN archive

Reintroduced the modsel_pipe arg to the model_selection() user function (the deleted modsel_run).

Modified the test_aic_mod_sel_diff_tensor() system test.

The model selection pipe will be created by the model_selection() use function, it doesn't need to
be precreated!

Converted the model-free model_statistics() method to the new relax design.

Some fixes for the model selection select() function - pipe switching was necessary.

Another fix for the checks in the test_aic_mod_sel_diff_tensor() system test.

Renamed the system test method for AIC model selection between two diffusion tensors.

The old name was test_diff(), whereas the new is test_aic_mod_sel_diff_tensor().

Fixed a self.assert_() call in the system test for AIC model selection between diffusion tensors.

Fixed the calls to count_num_instances() in the select() function.

Updated the model-free num_instances() method to the new relax design.

Branch deletion.