Made CDS reader allow for multiple lines of file descriptions
Tested multi-line file descriptions by altering test README file
Added note in CHANGES.rst
Added another CDS test
minor typo
Moved CHANGES.rst note to correct place
Included CDS data file for test
Merge pull request #2228 from hamogu/patch-1

minor typo
Included test file in setup_package
Merge pull request #2225 from amras1/cds-multiple-lines

Make CDS reader handle multiple description lines
Add dex, dB units; skip tests for mag,dB.decompose() for CDS, VOUNIT
since these do not know dex
Avoid clash between dB and decibyte=dbyte=dB
Add equivalency for logarithmic -> dimensionless, plus tests
Allow complex scale -- for (mag**0.5).decompose()
Fix coverage test
Another attempt to ensure __repr__ works on both python2 and 3, including for unicode units from CDS
Ensure u.mag ** 0.5 works
Add comments for why is_effectively_unity may have to deal with complex scale
Move import cmath to top
remove unnecessary import in core, two small PEP8 changes