Add spline debug plot

Relatively minimal at the moment--just focused on logic for debugging
which spline is running and what splines are planned.

Change-Id: Ic18aba9dd1e65eed173663854b124fe8c6ef353f
diff --git a/frc971/analysis/plot_index.ts b/frc971/analysis/plot_index.ts
index 4bf6c5a..56c99fa 100644
--- a/frc971/analysis/plot_index.ts
+++ b/frc971/analysis/plot_index.ts
@@ -24,6 +24,7 @@
 import * as proxy from 'org_frc971/aos/network/www/proxy';
 import {plotImu} from 'org_frc971/frc971/wpilib/imu_plotter';
 import {plotDrivetrain} from 'org_frc971/frc971/control_loops/drivetrain/drivetrain_plotter';
+import {plotSpline} from 'org_frc971/frc971/control_loops/drivetrain/spline_plotter';
 import {plotDownEstimator} from 'org_frc971/frc971/control_loops/drivetrain/down_estimator_plotter';
 import {plotRobotState} from
     'org_frc971/frc971/control_loops/drivetrain/robot_state_plotter'
@@ -90,6 +91,7 @@
   ['Demo', new PlotState(plotDiv, plotDemo)],
   ['IMU', new PlotState(plotDiv, plotImu)],
   ['Drivetrain', new PlotState(plotDiv, plotDrivetrain)],
+  ['Spline Debug', new PlotState(plotDiv, plotSpline)],
   ['Down Estimator', new PlotState(plotDiv, plotDownEstimator)],
   ['Robot State', new PlotState(plotDiv, plotRobotState)],
   ['Finisher', new PlotState(plotDiv, plotFinisher)],