Extend the code generation performed in _ModelMeta.__new__ to include generating __init__ methods as well.  This allows still more boilerplate to be removed from most Model subclasses (though it still allows individual subclasses to define their own __init__ when needed--see for example the polynomial models).
Remove the __init__ and __call__ generation from the custom_model decorator, since that part is now already handled (and somewhat better) by _ModelMeta.__new__
Fix typo in decorator per https://github.com/astropy/astropy/pull/2835/files#r16432656
For some reason the doc build is complaining about not having pages for the Pix2Sky/Sky2Pix base classes.  Unfortunately the only obvious way to add them is to include them in the module's __all__ even though they're not generally useful for users (though I guess useful as base classes for new projection types?)  If there's another way to do this let me know.  This is okay in the meantime though.
Made Latex/AASTex tables use unit attribute of Column for output
Added tests to coordinates, constants, convolutoin, cosmology
Reapplying changes ignored during rebase
Moved xfail code to before failure-inducing code.
xfailed convolution kernel tests
Merge pull request #2298 from ChrisBeaumont/memmap

Raise error if fits.open(memmap=True) is impossible.
Merge pull request #3019 from astrofrog/repeat-option

Added a --repeat option for testing
Merge pull request #2965 from mdboom/wcs-bounds-check

Correctly detect and handle invalid input world coordinates.
ModelMeta now creates a nicer __init__ definition for models that have no parameters.
Add missing support for keyword arguments to Pix2Sky_AZP
Reorder some of the API docs a bit.
Merge pull request #3052 from embray/table/issue-3052

Incorrect dtype format used for string columns when initializing Table from rows on Python 3
Just a minor detail--I noticed that the theta parameter has a default of 0.0 in the __init__, but this default is not given to the Parameter descriptor itself.
Updated docs to reflect changes in this PR; particularly that it is no longer generally useful to manually define an __init__ and __call__ (though an example of where it is useful to define a custom __init__ is given) and the roles of the input/output class attributes are discussed.
Enable InheritDocstrings on models.  Filled out several more docstrings that could use more details, and fixed __module__ and __qualname__ on generated __init__ and __call__ methods on models.
Fix spelling [skip-ci]