Provide suggestions when an exact unit match can not be found.
Add Returns clause to docstring
Handle unit suggestions by removing accents on Unicode characters,
e.g. ångström -> angstrom.  Fix some other Unicode-related issues.
Remove unused import
Add CHANGES.rst entry
Fix CHANGES.rst
Ensure lon, lat are passed on in Time addition/subtraction
Use different order of replicate/arithmetic to make keeping properties easier
Update documentation example
Ensure arithmetic keeps track of isscalar properly (plus tests)
Merge pull request #1929 from taldcroft/time-tdb-tt

Bug in TDB to TT calculation
Merge pull request #1927 from mhvk/time-keep-lon-lat-in-arithmetic

Ensure all relevant Time attributes are passed on in Time addition/subtraction
Merge pull request #1870 from mdboom/unit/recommend

Recommend alternatives when a unit isn't found
Update MaskedColumn to fix unicode column names like in Column
Fix u'' syntax, not in python 3.1, 3.2
Merge pull request #1934 from taldcroft/table/fix-masked-col-name

Update MaskedColumn to fix unicode column names like in Column
Squashed commits for masked column pattern change

  Make our MaskedColumn like the example in numpy.ma.tests.test_ma.MSubArray
  Updated implementation; Passes all but 2 tests
  Move most Column stuff into BaseColumn
  Add option to allow converting MaskedColumn to Column in BaseColumn
  Copy mask and change so mask len must match array len
  Add Column.__new__ which mostly calls BaseColumn.__new__, and some cleanup
  Strip off the BaseColumn-ness for repr and str to fix MaskedColumn repr
  Rewrite copy so it works for both Column and MaskedColumn
  Need to adjust fill_value in MaskedColumn.copy
  Remove unnecessary BaseColumn.__str__, MaskedColumn.__array_finalize__
  Further unify copy by making BaseColumn version fully general; improve docstring
  Set fill_value via setter, not MaskedArray constructor
  Residual cleanup from rebase
  Make MaskedColumn inherit from Column to get output methods
  Use six.callable for compatibility with Python 3.1
  Remove a misplaced str() conversion
  Update CHANGES.rst
When initing from BaseColumn instance w/o attrs, don't try using those attrs