pytest 3.0 checklist

The following changes will be part of the 3.0 release as discussed at the pytest sprint 2016 in Freiburg.

Definitely

--setup-show,--setup-only, --setup-plan options
reporting hooks for fixture setup/teardown (Steffen, Danielle)
new main entry point pytest (and py.test)
remove py.test-X* entrypoints
doc restructuring
display pytest warnings by default
remove all deprecated command line options for 3.0 (Farmer)
fixture conftest sharing / fixture namespace control, draft/suggestion document
merged fixtures becomes a doc draft (Raphael, Holger)
introduce deprecation docs based on lightning talk (Oliver)
new option --override-ini|-o ININAME=INIVALUE to overrides ini values from the command line so that one can do e.g. -o xfail_strict=True. We don't change the default (Omar, Ted, Daniel)
issue deprecation warning for yielding test functions (bruno)
issue deprecation warning pytest_funcarg_ fixtures (bruno) (#1684)
remove reinterpret assert (Floris)
invocation-scope: e.g. monkeypatch and mocker would be useable from any scope. Will be marked experimental for 3.0. (In review, Bruno)

Issues and PRs for the 3.0 milestone: https://github.com/pytest-dev/pytest/milestone/2 (42 currently!)