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

wpilibj/src/main/native/cpp/ConstantsJNI.cpp

@@ -0,0 +1,42 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. 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 <assert.h>
+#include <jni.h>
+#include "HAL/cpp/Log.h"
+
+#include "edu_wpi_first_wpilibj_hal_ConstantsJNI.h"
+
+#include "HAL/Constants.h"
+#include "HALUtil.h"
+
+using namespace frc;
+
+// set the logging level
+TLogLevel constantsJNILogLevel = logWARNING;
+
+#define CONSTANTSJNI_LOG(level)     \
+  if (level > constantsJNILogLevel) \
+    ;                         \
+  else                        \
+  Log().Get(level)
+
+extern "C" {
+/*
+ * Class:     edu_wpi_first_wpilibj_hal_ConstantsJNI
+ * Method:    getSystemClockTicksPerMicrosecond
+ * Signature: ()I
+ */
+JNIEXPORT jint JNICALL
+Java_edu_wpi_first_wpilibj_hal_ConstantsJNI_getSystemClockTicksPerMicrosecond(
+    JNIEnv *env, jclass) {
+  CONSTANTSJNI_LOG(logDEBUG) << "Calling ConstantsJNI getSystemClockTicksPerMicrosecond";
+  jint value = HAL_GetSystemClockTicksPerMicrosecond();
+  CONSTANTSJNI_LOG(logDEBUG) << "Value = " << value;
+  return value;
+}
+}