Beta release 0.7.3

Changes since 0.7.1:

• Throw PIDException to publisher on reconnection failure even if publisher has called close in the meantime.
• Make sure that force finish interrupts the cycle of reconnection attempts.
• Gentle-closing algorithm stops after force-finish.
• Make sure that enough publishes are triggered, even if events are not processed correctly during reconnect.

Note: There is no release for 0.7.2, which is technically the same as 0.7.3.