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
Update _wrap_function doc string, correct and test nansum out option
Made Latex/AASTex tables use unit attribute of Column for output
Initial step in removing ndarray from Table
Continued migration, down 117 test fails
Fix sort and argsort
WIP fixing __setitem__
Add basic functionality for table-level setitem
Remove separate Row-based setter
Basic row setting working
Fix masking, allow for list column input by reference
Final updates, passes table tests
Add copy kwarg to BaseColumn
Initial support for non-Column columns
Initial integration of Quantity