Fix problems with 0-threshold trigger algorithm

[joefowler]

Jamie at NSLS-II is having weird data problems that seem to imply 0-threshold triggering is not working 100%. See Feb 17 conversations and notes. Will need to look at LJH/OFF data to diagnose. Hope is that the problem is simply one of numerical parameters in the algorithm?

[ggggggggg]

This is still an issue, we determined that the zero threshold is working, it just not tuned to put the phase correction kink right at the boundary. So we still need to tune the zero threshold algorithm, probably just by tweaking a few numbers.