add exception back in

MiniLib/src/edu/wpi/first/wpilibj/command/IllegalUseOfCommandException.java

@@ -0,0 +1,36 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2008-2018 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.wpilibj.command;
+
+/**
+ * This exception will be thrown if a command is used illegally. There are several ways for this to
+ * happen.
+ *
+ * <p> Basically, a command becomes "locked" after it is first started or added to a command group.
+ * </p>
+ *
+ * <p> This exception should be thrown if (after a command has been locked) its requirements change,
+ * it is put into multiple command groups, it is started from outside its command group, or it adds
+ * a new child. </p>
+ */
+public class IllegalUseOfCommandException extends RuntimeException {
+  /**
+   * Instantiates an {@link IllegalUseOfCommandException}.
+   */
+  public IllegalUseOfCommandException() {
+  }
+
+  /**
+   * Instantiates an {@link IllegalUseOfCommandException} with the given message.
+   *
+   * @param message the message
+   */
+  public IllegalUseOfCommandException(String message) {
+    super(message);
+  }
+}