Update to 2018_v4 image and new build system. (#598)

* Revert "Force OpenCV to 3.1.0 (#602)"

This reverts commit 50ed55e8e2.

* Removes Simulation

* Removes old build system

* Removes old gtest

* Adds new gmock and gtest

* Updates to new ni-libraries

* removes MyRobot (to be replaced)

* moves files to new location

* Adds new sim backend and new test executables

* updates .styleguide and .gitignore

* Changes cpp WPILibVersion to a function

MSVC throws an AV with the old version.

* Disables USBCamera on all systems except for linux

* 2018 NI Libraries

* New build system

wpilibc/src/main/native/cpp/PIDSource.cpp

@@ -0,0 +1,21 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2017. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "PIDSource.h"
+
+using namespace frc;
+
+/**
+ * Set which parameter you are using as a process control variable.
+ *
+ * @param pidSource An enum to select the parameter.
+ */
+void PIDSource::SetPIDSourceType(PIDSourceType pidSource) {
+  m_pidSource = pidSource;
+}
+
+PIDSourceType PIDSource::GetPIDSourceType() const { return m_pidSource; }