Focus Analyze Bug

Bug reported by Hy whereby the v-curve shown in Analyze differs from that in Focus.

Looks like 2 issues:

1. Separate plot_ vectors used in for the signal to Analyze not being kept in line with vectors used in focusalgorithms. Fixed.
2. Appears that overscan failed. That triggered a series of events that lead to point 1. which lead to analyse receiving a signal from Focus containing bad data. Added logging to try and pinpoint the exact problem.

Can't reproduce 2. but hopefully the extra logging will help.

Tested on sims for all focus algos.