Merge pull request #285 from btovar/wq_throttle_resources_msgs

Send resources updates at least five seconds apart to lower the chances of saturating the master link while the master is busy doing something else.
send_master_message now returns total bytes written.
Add list for completed tasks to be sent back to the master.
Send a single available_results message.
worker sends completed tasks on "send_results".
Wait for result messages when receiving 'available_results'.
Foreman sends completed tasks on "send_results"
Keep a list of workers with available results.
process_*result? did not use stoptime as a parameter.
Print foreman's disk usage only when updating resources.