Repackage CameraServer classes (#1321)

This is necessary for modularization.
Move the wpilibj CameraServer classes to the cameraserver package.
Move the edu.wpi.first.wpilibj.vision package to edu.wpi.first.vision.
To avoid code breakage, add deprecated copies of the wpilibj classes to the wpilibj jar.

cameraserver/src/main/java/edu/wpi/first/vision/VisionPipeline.java

@@ -0,0 +1,26 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2016-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.vision;
+
+import org.opencv.core.Mat;
+
+/**
+ * A vision pipeline is responsible for running a group of
+ * OpenCV algorithms to extract data from an image.
+ *
+ * @see VisionRunner
+ * @see VisionThread
+ */
+public interface VisionPipeline {
+  /**
+   * Processes the image input and sets the result objects.
+   * Implementations should make these objects accessible.
+   */
+  void process(Mat image);
+
+}