Make sundry improvements/bug fixes to auto-aiming

This includes:
-Adding some velocity and voltage limits to prevent excessive
 velocity and acceleration.
-Logging more information in the status message.
-Fixing calculation of the desired turret velocity.

Change-Id: I83840bc1db9dda003be63e594d826fc97fa509e8
diff --git a/y2020/constants.cc b/y2020/constants.cc
index 463919a..eefc158 100644
--- a/y2020/constants.cc
+++ b/y2020/constants.cc
@@ -76,7 +76,7 @@
 
   // Turret Constants
   turret_params->zeroing_voltage = 4.0;
-  turret_params->operating_voltage = 12.0;
+  turret_params->operating_voltage = 8.0;
   // TODO(austin): Tune these.
   turret_params->zeroing_profile_params = {0.5, 2.0};
   turret_params->default_profile_params = {15.0, 40.0};