Fix #2559: Make equivalencies work correctly with compose.
Add another compose-to-equivalencies example.
Fix tests
Fixed error in io.ascii on Mac
Added a --repeat option for testing
Added repeat option to test()
Correctly detect and handle invalid input world coordinates.
Add CHANGES entry
Added an additional test and workaround for #3052.
Default ``data_start`` to 0 in ``CommentedHeader``

fixes #2692
Ensure Quantity.round always works; wrap methods with less boilerplate
Adapt places where "wrong" np.round led to the right result
Add changelog entry [skip ci]
Ensure test_std_inplace always fails, as it is broken in numpy
Avoid keyword arguments where possible to resolve numpy 1.5 failures
Raise error if fits.open(memmap=True) is impossible.
Update _wrap_function doc string, correct and test nansum out option
Early experiment in giving names to model input/output coordinates, rather than just counts of inputs/outputs.
Break _ModelMeta.__new__ into a few subroutines for readability.  Brings the same code generation used by custom_model to the main Model class itself for __call__ methods.  Now it's generally unnecessary for Model subclasses to redefine __call__ even if they want to update the method signature to reflect the names of their inputs.  That is now automatic.  Also the Model base class no longer makes any assumptions about the number of a model's inputs or outputs.  It assumes no inputs/outputs until otherwise specified in a subclass.
Fix some minor issues with the array-like interface to Parameters that came up, interestingly, when trying to call help() on a model class.