some syncAndCrunch samples are not completing as normal

[raacampbell]

RS also sees this randomly.
No images to web and the command line reports it gets stuck on a section with zero images even though there are more data.

[raacampbell]

It seems that if there is an error that causes a crash then the web preview loop stays dead until it's next restarted. But when that happens it will not regenerate another image until an extra section has been created since it was last started. This can create a very long period during which seemingly nothing is updated. First step is to have it generate a webpreview image regardless so long as there is at least one complete section (3d1f63e).

Next I think we need to:

• generate time-stamped messages
• write to a log file in the section directory
• keep writing to this file. do not over-write when we re-start the web preview. so we have a log of what has gone wrong in the past.
• Reduce log length by shortening messages, like the generateTileIndex stuff

I currently see a lot of errors that state:

Building main image with buildSectionPreview: section 99, opticalSection 1, all channels
tileLoad - Can not find stack rawData/YJ_221122_DATTOM-0099/YJ_221122_DATTOM-0099_00183.tif. RETURNING EMPTY DATA. BAD.
Failed to load data from section 99/1 channel 2.

This is odd because they all eventually work. Maybe we have a hardware error brewing?