Makes the CANJaguar error status messages more useful (#165)

The previous version would just return the class name for the
DigitalOutput port. Now it actually gets the dio port value for better
readability.

wpilibj/src/athena/java/edu/wpi/first/wpilibj/DigitalOutput.java

@@ -64,6 +64,15 @@ public class DigitalOutput extends DigitalSource implements LiveWindowSendable {
     DIOJNI.setDIO(m_handle, (short) (value ? 1 : 0));
   }
 
+  /**
+   * Gets the value being output from the Digital Output.
+   *
+   * @return the state of the digital output.
+   */
+  public boolean get() {
+    return DIOJNI.getDIO(m_handle);
+  }
+
   /**
    * @return The GPIO channel number that this object represents.
    */