minor README.md updates
pep8 fixes

Fix the following pep8 issues:
redmine_interface.py:21:80: E501 line too long (95 > 79 characters)
redmine_interface_test.py:9:11: E225 missing whitespace around operator
redmine_interface_test.py:13:1: E302 expected 2 blank lines, found 1

Also add hint to console printout about what might be needed if Redmine
support is not enabled.