Adds JNI Simulator interface and updated Sim API (#1002)

The simulator was generated by https://github.com/ThadHouse/SimulatorGenerator

hal/src/main/native/sim/jni/SimulatorJNI.h

@@ -0,0 +1,25 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2018 FIRST. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <wpi/jni_util.h>
+
+#include "HAL/Types.h"
+#include "MockData/HAL_Value.h"
+#include "jni.h"
+
+typedef HAL_Handle SIM_JniHandle;
+
+namespace sim {
+JavaVM* GetJVM();
+
+jmethodID GetNotifyCallback();
+jmethodID GetBufferCallback();
+jmethodID GetConstBufferCallback();
+jmethodID GetSpiReadAutoReceiveBufferCallback();
+}  // namespace sim