################
#           To Do:
################
 
Should TimeSeriesModel be extended or listened to for Rotation-specific behaivor?

Test at 1024x768

On rotational motion sim, lots of it worked well and looked good, but when showing acceleration a, the zero and the curve was below bottom of graph sometime.  Angular acceleration  worked well though.

Performance optimization.

Graphs shouldn't fill entire vertical space when there is only 1.

When the time series is off-scale, dragging the slider doesn't immediately respond.
Clicking on the slider thumb should set the current value, and allow immediate drags.

Time series implementation.

Add a graph cursor.

Time derivatives need a time-offset to match other series.

Time series are offset incorrectly in graphs (their x-offset is before the beginning of the graph).

Angle graphs should wrap around instead of being modulo 2*Pi.

When resizing a graph, the layout can change (due to difference in axis labels), so realignment should be done after any data area changes.

################
#           Postponed:
################
Try 2nd order derivative directly from position data..?