Loosened all of the model-free tests so that the minimisation statistics are no longer checked.
The same result was being obtained on different platforms, different Python versions, and different
numpy versions, but the minimisation statistics were slightly different. The iter, f_count, g_count
h_count, and warning variables are no longer checked. This will stop users from thinking they have
a problem with their version of relax, after running the test suite.
