The binary wheels edition

This is the first release that will be supplied as binary wheels
(manylinux2010). Note that you need pip > 10.x to use manylinux2010 wheels.
If you don't use the binary wheel and unicode is important to you, use
casacore 3.1.1. Note that we skipped 3.1.0 to match the casacore version
and hopefully avoid confusion.

Changes:

• handle unicode even better! :) (#158)
• iteritems() in casacore/tables/table.py incompatible with Python 3 (#165)
• Make a big binary wheel including dependencies (#145)
• Use ~ instead of - to negate the mask (#179)