Add more verbose debugging options for accelerate
Added keepalive packets to accelerate mode

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.
Adding an accelerate_timeout parameter for plays

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
Added in an accelerate connection timeout setting
Removing accelerate_timeout as a playbook option

This will remain in ansible.cfg only.
Cleaning up some vvvv log messages in accelerate
Drop default config value for accelerate timeout to 30 seconds
Make recv_data less greedy so it doesn't eat other packets
Merge branch 'accelerate_improvements' into devel

Conflicts:
	library/utilities/accelerate