`qraat.estinterval.A` = pulse variation.

Calculate the second moment around the mode. Modified plot_score.py
to plot this.
More useful legend.
Playing with a solution ...
Merge branch 'master' into tracking
Updated `qraat.estinterval`, updated code.
scripts/filter/score_error.py: Partition good/bad points.
score_error.py: Output result.
score_error.py: dump result via pickle.
Started plot_score_error.py.
Think I got it ...
SCORE_ERROR a function of est interval variation.
Flipped input to imshow().
Merge branch 'master' into tracking
Simple function for pulse error.