Merge pull request #1457 from Microsoft/extra_comma

remove trailing comma at the end of optionDeclarations array

src/compiler/commandLineParser.ts

@@ -133,7 +133,7 @@ module ts {
             shortName: "w",
             type: "boolean",
             description: Diagnostics.Watch_input_files,
-        },
+        }
     ];
     
     var shortOptionNames: Map<string> = {};