Click warns about using unicode_literals

[cfournie]

When using important, Click warns about using the unicode_literals future import:

.../python2.7/site-packages/important/__main__.py:67: Warning: Click detected the use of the unicode_literals __future__ import.  This is heavily discouraged because it can introduce subtle bugs in your code.  You should instead use explicit u"" literals for your unicode strings.  For more information see http://click.pocoo.org/python3/