Added max_mem_abs and min_mem_abs to ResourceWatcher
Added human2bytes to utils.py
Added test for max and min abs mem of ResourceWatcher
Added documentation for max and min abs mem of ResourceWatcher
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
Fixed flake8 warnings, adpated tests to async architecture
Removed useless backslashes
Merged max_mem_abs and max_mem (same for min)
Rewrote util.human2bytes + unit tests
fixed doc
Fixed if syntax
Polishing code
add a sequential option to the reload command for #646
add basic test
fixed typo
Modify config.py for combining the same condition code
move list to tuple
Move check_flapping to default True group
Delete pids that don't have recent stats
Merge pull request #697 from dongweiming/modify_config

Modify config.py for combining the same condition code
Added circus-top CLI argument process-timeout