Update the IGraph Interface documentation.

Fixed the documentation for the addEdge() and addUndirectedEdge()
methods to indicate that the graph should still be updated even if the
edge is already present.

src/edu/caltech/cs2/interfaces/IGraph.java

@@ -14,7 +14,7 @@ public abstract class IGraph<V, E> {
      * @param e The edge to add.
      * @throws IllegalArgumentException
      *             If e is not a valid edge (eg. refers to vertices not in the graph).
-     * @return true If e was not already present; false if it was (in which case the graph is not updated).
+     * @return true If e was not already present; false if it was (in which case the graph is still updated).
      */
     public abstract boolean addEdge(V src, V dest, E e);
 
@@ -24,7 +24,7 @@ public abstract class IGraph<V, E> {
      * @param e The edge to add.
      * @throws IllegalArgumentException
      *    If e is not a valid edge (eg. refers to vertices not in the graph).
-     * @return true If e was not already present in either direction; false if it was (in which case the graph is not updated).
+     * @return true If e was not already present in either direction; false if it was (in which case the graph is still updated).
      */
     public abstract boolean addUndirectedEdge(V src, V dest, E e);