update URLs for issues and others
fix dates and license
fix magic lines
cleanup imports and module docstrings
use explicit imports
use consistent from __future__ in neo core
doc conf and examples pep8 cleanup
update documentation on documentation and other bits of documentation
cleanup imports and module docstrings
pep8 cleanups for the rest of neo
pyflakes cleanups
classes with extra dependencies should fail on init rather than import so the docs still build
update test skips
update which versions of python 3 are compatible