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/EnumFormatter.java b/core/api/src/main/java/org/onosproject/ui/table/cell/EnumFormatter.java
index e8e41e8..7a8d9aa 100644
--- a/core/api/src/main/java/org/onosproject/ui/table/cell/EnumFormatter.java
+++ b/core/api/src/main/java/org/onosproject/ui/table/cell/EnumFormatter.java
@@ -30,7 +30,7 @@
 
     @Override
     protected String nonNullFormat(Object value) {
-        return capitalizeFully(value.toString().replace("_", " "));
+        return capitalizeFully(value.toString().replace(UNDERSCORE, SPACE));
     }
 
     /**