[1.x] Optionally uses control frames for handling ping and pong

[joedixon]

This PR attempts to resolve #224

It's been reported that some of the Pusher clients don't support the pusher:ping|pong event format for handling pings and pongs and will, instead, rely on the low-level ping/pong control frames provided by the WebSocket specification.

This PR aims to address that by:

• Defaulting to Pusher's pusher:ping|pong
• Updating the last active timestamp on the connection when receiving a low-level ping control frame. The aim here is to prevent connections getting pruned by the PruneStaleConnections job
• Set a boolean status on the connection of usesControlFrames when receiving a low-level ping control frame and, when this value is true, send low-level ping control frames when running the PingInactiveConnections job.

[joedixon]

Had some good feedback to this PR on #224 so bringing this out of draft.