Improve SC algorithm by using a better initial phi.

Start improvement by using a more robust initial phi value. For the
simulated data we know this is zero, but in real life this could come
from some algorithm.
More improvements to robustness of SC.

Fix thresholding so that we included NaN SNR values. Also, use
smoothed phidp to find the end point. Adjustments to some thresholds.
More work on testing SC.

Have working copy of algorithm, tweaks to plots.