Dispute opener upgrades

[weex]

1. The dispute should be able to include a signed primary payment transaction. The mediator obviously would only sign one they thought was fair, but this can make the process quicker
2. The resulting document should also include the mediator's contact info, though it may make sense to upgrade status --jobid instead so it formats available for easy reading.

[weex]

7279fcd summarizes the data shown in a status --jobid command into one dict before pretty printing it.