Move PDP measurement fetching to a separate thread

Stupid CAN messages are too slow for being inline with the normal
path...

Change-Id: I160a24eb3216fc54083df576555b5bcad062ceb8
diff --git a/y2015/wpilib/BUILD b/y2015/wpilib/BUILD
index c5c4202..6966c9f 100644
--- a/y2015/wpilib/BUILD
+++ b/y2015/wpilib/BUILD
@@ -33,5 +33,6 @@
     '//frc971/control_loops:queues',
     '//frc971/wpilib:logging_queue',
     '//frc971/wpilib:wpilib_interface',
+    '//frc971/wpilib:pdp_fetcher',
   ],
 )