Add idempotency support to ec2_group

asn1 is a dependency so no need to mention this in docs.  Also no callouts for other OSes so no need for BSD.

Conflicts:
	library/utilities/accelerate

htpasswd docs: add notes about depending on python-passlib

ec2_eip module: note that there may be a delay reaching the instance

Added comment which two packages are needed on FreeBSD.

This will remain in ansible.cfg only.

This setting makes the timeout for each play configurable, rather than
hard-coding it at 300 seconds (now the default if left unspecified)

Fixes #4162

Commands will now be started up in a separate task from the main
handler thread, so that it can be monitored for completeness while
sending a keepalive packet back to the controller to avoid a socket
receive timeout.

Fixes #4321

Fixes #4322

Merge branch 'fixes/subprocess' of https://github.com/ferringb/ansible into ferringb-fixes/subprocess

In the script action: Get around a Python bug.

Merge branch 'source_control-executable' of https://github.com/skyl/ansible into skyl-source_control-executable

Merge branch 'role_report_fix1' of https://github.com/bennojoy/ansible into bennojoy-role_report_fix1

Merge branch 'hide_skipped_hosts' of https://github.com/jsmartin/ansible into jsmartin-hide_skipped_hosts