Adjusted coverage plot so lines stop at 0 when coverage reaches 0
Adjusted coverage plot so lines stop at 0 when coverage reaches 0

Lines in coverage plot now drop to 0 when coverage reaches 0 but lines do
not extend across the entirety of 0 coverage stretch.

Plot size also adjusted to not look so stretched out.

svohr/mixemt,svohr/mixemt,svohr/mixemt