reset value at the end of cycle
issue #65: sort scatter series by name
issue #52: appended missing values have y=null
issue #52: fix labels
issue #56: compute x plotLine
issue #56: compute y plotline
issue #56: compute y plotLine for non multiseries
issue #56: refactor App.format_plotLines
issue #56: add plotlines to chart if instructed
issue #56: add only specified plotlines
issue #56: use horizontal plotline on columns
issue #56: add plotlines to array axis
issue #56: refactor add_plotLines
issue #56: add plotlines to scatter scenario
Merge branch 'various-fixes'