Merge remote-tracking branch 'upstream/master' into ressource-watcher-mem-abs

Conflicts:
	circus/plugins/resource_watcher.py
	circus/tests/test_plugin_resource_watcher.py
	docs/source/for-ops/using-plugins.rst
Example of lossless reload in uWSGI
Merge pull request #639 from scottkmaxwell/uwsgi_example

Example of lossless reload in uWSGI
prep for release
Add extended_stats hook
Merge pull request #640 from scottkmaxwell/extended-stats-hook

Add extended_stats hook
Fixed flake8 warnings, adpated tests to async architecture
fixed images links
starting 0.11
more images fix
one more image link
fixed all the paths non-sense
added missing files
arbiter:  fix autostart=False watchers during start

In ebec3e50ec3e804caa9df0275d547e07705deae9 arbiter.start() switched
from using arbiter.start_watcher() to using arbiter.start_watchers().
The later does not respect the autostart attribute for each watcher.
This is a regression from behavior in 0.9.2.

Fixed by checking watcher.autostart in arbiter._start_watchers() and
added a unittest to check this in the future.
fixed mockup - fixes #644
place py27 first to try to make coveralls happy
run coveralls only with py27
Merge pull request #643 from jsbronder/autostart_fix

arbiter:  fix autostart=False watchers during start
make sure we have >= 13.1.x
fixed the check_delay typo and allow it to be a float - fixes #651