Update WPILib, roborio compilers, and CTRE Phoenix libraries

This borrows heavily from work that Ravago did to initially get this
stuff working.

Tested rudimentary functionality on a test bench, ensured that we could:
* Enable the robot.
* Read joystick and button values.
* Switch between auto and teleop modes.
* Read sensor values (encoder, absolute encoder, potentiometer).
* Read PDP values.
* Drive PWM motors.
* Drive CANivore motors.

Non-WPILib changes are made to accommodate the upgrade roborio
compiler's improved pickiness.

Merge commit '125aac16d9bf03c833ffa18de2f113a33758a4b8' into HEAD

Change-Id: I8648956fb7517b2d784bf58e0a236742af7a306a
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/aos/events/logging/log_edit.cc b/aos/events/logging/log_edit.cc
index 969d59c..e3cfc3a 100644
--- a/aos/events/logging/log_edit.cc
+++ b/aos/events/logging/log_edit.cc
@@ -55,7 +55,7 @@
 
     while (true) {
       absl::Span<const uint8_t> msg_data = span_reader.ReadMessage();
-      if (msg_data == absl::Span<const uint8_t>()) {
+      if (msg_data.empty()) {
         break;
       }