Only display remaining time to 1 decimal place
Only display remaining time to 1 decimal place

The C++ reconstruction was using quite a large accuracy, this makes the
layout jitter, and is also not particularly useful. Just show seconds
estimated to the nearest single decimal place and the dialog is more
stable with an estimate that is easier to read.

mathturtle/tomviz,mathturtle/tomviz,OpenChemistry/tomviz,cjh1/tomviz,mathturtle/tomviz,cjh1/tomviz,OpenChemistry/tomviz,thewtex/tomviz,cryos/tomviz,thewtex/tomviz,cryos/tomviz,thewtex/tomviz,cryos/tomviz,OpenChemistry/tomviz,cjh1/tomviz,OpenChemistry/tomviz