data.py: don't crop segments shortet than 1 sample
data.py: allow arbitrary TimeSeries storage
DataSummaryPlot.tag: cchar sub in type
DataSummaryPlot.finalize: two changes

    - fix x-axis ticklabels being too close to axis
    - allow custom outputfile (returns outputfile that was used)
plot.builin: multiple small changes/bug fixes
TriggerRateSummaryPlot: added trigger rates
SimpleStateTab: added support for trigger-rate