Updated C++ documentation

Fixed incorrect documentation for Task class, improved documentation for RobotDrive's drive() function (thanks to FRC Team 4579), and ran doxygen -u on cpp.doxy to remove deprecated XML_SCHEMA and XML_DTD tags

Change-Id: I2f3fa4018d69b84e67376a5feb0eca43d5fa7623

wpilibj/wpilibJavaSim/src/main/java/edu/wpi/first/wpilibj/RobotDrive.java

@@ -176,16 +176,24 @@ public class RobotDrive implements MotorSafety {
     }
 
     /**
-     * Drive the motors at "speed" and "curve".
+     * Drive the motors at "outputMagnitude" and "curve".
+     * Both outputMagnitude and curve are -1.0 to +1.0 values, where 0.0
+     * represents stopped and not turning. curve < 0 will turn left and curve > 0
+     * will turn right.
      *
-     * The speed and curve are -1.0 to +1.0 values where 0.0 represents stopped and
-     * not turning. The algorithm for adding in the direction attempts to provide a constant
-     * turn radius for differing speeds.
+     * The algorithm for steering provides a constant turn radius for any normal
+     * speed range, both forward and backward. Increasing m_sensitivity causes
+     * sharper turns for fixed values of curve.
      *
      * This function will most likely be used in an autonomous routine.
      *
-     * @param outputMagnitude The forward component of the output magnitude to send to the motors.
-     * @param curve The rate of turn, constant for different forward speeds.
+     * @param outputMagnitude The speed setting for the outside wheel in a turn,
+     *        forward or backwards, +1 to -1.
+     * @param curve The rate of turn, constant for different forward speeds. Set
+     *        curve < 0 for left turn or curve > 0 for right turn.
+     * Set curve = e^(-r/w) to get a turn radius r for wheelbase w of your robot.
+     * Conversely, turn radius r = -ln(curve)*w for a given value of curve and
+     * wheelbase w.
      */
     public void drive(double outputMagnitude, double curve) {
         double leftOutput, rightOutput;