Cleaning up Javadocs in core-ui classes.
Added common constants to AbstractCellFormatter.

Change-Id: Ie20ea62f059646e7d6c7f3660dd60a60c40532fe
diff --git a/core/api/src/main/java/org/onosproject/ui/table/cell/ConnectPointFormatter.java b/core/api/src/main/java/org/onosproject/ui/table/cell/ConnectPointFormatter.java
index f64c296..7d9964f 100644
--- a/core/api/src/main/java/org/onosproject/ui/table/cell/ConnectPointFormatter.java
+++ b/core/api/src/main/java/org/onosproject/ui/table/cell/ConnectPointFormatter.java
@@ -30,7 +30,7 @@
     @Override
     protected String nonNullFormat(Object value) {
         ConnectPoint cp = (ConnectPoint) value;
-        return cp.elementId() + "/" + cp.port();
+        return cp.elementId() + SLASH + cp.port();
     }
 
     /**