Fix four HTTP proxying problems.
 * Added "Connection: close" to 5xx errors.
 * Properly close both upstream and downstream connections on errors.
 * Fixed infinite loop when responding to HEAD requests that have no body.
 * Fixed randomness when using keep-alive connections. Previously, the behavior
   was only randomly selected on new connections, but HTTP keep-alive connections
   need to choose a random behavior for each new request/response.
CLI option correction: behavior rather than handler

I think the correct delay option is behavior rather than handler.
Merge pull request #23 from deanwilson/master

CLI Example correction
Merge pull request #22 from jterrace/fix-http2

Fix four HTTP proxying problems.
Merge pull request #20 from dax/optional_host_rewrite

Add an option to disable HTTP Host header overwrite
bumped version
style
Distinguish behaviors blackout & hang in comments & documentation
Merge pull request #25 from ethanmiller/master

Comments for blackout behavior
Add abort behavior

This behavior abort a connection while receiving the response from the server.
Some servers may fail to handle successfully sending the response but still receiving an aborted connection before it can close it.