Added rotational/linear masses to python subsystem files.

Change-Id: I16c245771745409f04a53e3fc2d1a3f179ab67b8
diff --git a/y2019/control_loops/python/stilts.py b/y2019/control_loops/python/stilts.py
index 8faa5d4..b07321c 100755
--- a/y2019/control_loops/python/stilts.py
+++ b/y2019/control_loops/python/stilts.py
@@ -21,7 +21,7 @@
     # 5mm pitch, 18 tooth
     radius=0.005 * 18.0 / (2.0 * numpy.pi),
     # Or, 2.34 lb * 2 (2.1 kg) when lifting back up
-    mass=40.0,
+    mass=1.175 * 2,  # 1 stilt foot = 1.175 kg
     q_pos=0.070,
     q_vel=1.2,
     kalman_q_pos=0.12,