Some internal tweaks

Nothing particularly user-visible in this one. A few significant items internally:

• Increased diagnostics while Spaces are booting up, to try and get my hands around why the SI Playtesting Space seems to be frequently failing to start successfully.
• An attempt, when things do fail to start, to shut down the Space so that subsequent tries have some hope of succeeding. (This is hypothetical, and may not work for all types of failures.)
• Made the Admin tool to forensically dump the history of a Space a bit more controllable.

Also, reformatted all of the code using scalafmt, to reduce formatting churn going forward.