add a sequential option to the reload command for #646
add basic test
Delete pids that don't have recent stats
Added circus-top CLI argument process-timeout
validPid renamed to valid_pid
no concurrent execution during arbiter restart

An explicit test is needed because the restart()
command is a kind of stop() command. The start after
the stop is made (externally) by circusd for plenty of reasons.

So the restart() command is over before the arbiter is really restarted.
So the classic synchronized decorator is released too early.

see #714
fix the add command to respect the rlimit_* settings

- add special logic for validation rlimit_* keys when used from the
add command that matches the way rimit_* options are processed via
the conf file
- added a test for the rlimit_* validations
allow you to override the virtualenv command to one in your environment
Merge pull request #719 from wynnw/feature/add-rlimit-fixes

Feature/add rlimit fixes
Merge pull request #704 from pomarec/fix.circustop-clean-old-pids

Circus-top : delete pids that don't have recent stats
new feature for setting the ipc endpoint socket owner

- Added a new config option called 'endpoint_owner' that must be set to
a unix user name
- When the endpoint is an ipc connection and endpoint_owner is set, then
the ipc socket file will be chown'd to the endpoint_owner user value.
This allows circus to run as root but allow certain processes to send
commands to it without having to run as root.
update the docs for the new endpoint_owner functionality
add an entry to the contributors list for me
Merge pull request #718 from thefab/fix714

Fix #714
Merge pull request #683 from thefab/fix646

add a sequential option to the reload command for #646
Merge pull request #720 from wynnw/feature/endpoint-owner

new feature for setting the ipc endpoint socket owner