Quite WIP.  Have marked some TODOs.  Will add some provisional changes to
manager.

In testing, I just found a typo I made yesterday.  Also, reopening the
SharedMemory even readonly was failing, so I set the bridge to only open once
and then change view (as it should, to be fair).  Will think about nice
encapsulation of this.

Was trying to map out behavior of DsscGpuRunner as an FSM and found that this
was missing.