time series GUI mostly figured out
reorganizing, and incorporating dev_test results
Several changes. Major changes shown below:
* src/semicontrol/gui/time_series.py
    * TimeSeriesPlotDataItem
        * sped up appending to log plots by using extra RingBuffers
        * fixed 'clear' method
    * TimeSeriesAxis
        * fixed TypeError on dragging axis
    * TimeSeriesWidget
        * switched to using TimeSeriesPlotItem
    * added test or sample code for if run as script