nix: don't inject invoke/bumpversion in default shell, we use our own py3 compat, and want to have an option to skip it

ini: updated .ini templates

gunicorn: updated gunicorn config based on release changes

cython: fixed problems with cythonized decorators on py2. - This is just a temporary fix - We'll remove this once py3 migration is done

release: updated API docs

docs: updated formatting for release docs 4.18.X

docs: updated performance/tunning docs according to latest code changes

config: small updated to .ini files

docs: added release notest for 4.18.X

configs: use new style of comments on .ini files. - This will allow better diffing options with control mako templates - main problem was ## comments which in mako we needed to escape. - cleanup configurations with some nicer formatting/comments