Renamed the Pair.left and Pair.right fields to Pair.first and Pair.second

This is done for consistency with the C++ "std::pair" class template
from the STL (Standard Template Library).
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java b/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java
index a617839..2245758 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java
@@ -3,18 +3,18 @@
 /**
  * A generic class representing a pair of two values.
  */
-public class Pair<L, R> {
-    public L left;		// The first value in the pair
-    public R right;		// The second value in the pair
+public class Pair<F, S> {
+    public F first;		// The first value in the pair
+    public S second;		// The second value in the pair
 
     /**
      * Constructor for a pair of two values.
      *
-     * @param left the first value in the pair.
-     * @param right the second value in the pair.
+     * @param first the first value in the pair.
+     * @param second the second value in the pair.
      */
-    public Pair(L left, R right) {
-	this.left = left;
-	this.right = right;
+    public Pair(F first, S second) {
+	this.first = first;
+	this.second = second;
     }
 }