adhere to tslint rules

Author: tiagoschenkel

src/robotlegs/bender/extensions/signalCommandMap/impl/SignalCommandMap.ts

@@ -72,8 +72,10 @@ export class SignalCommandMap implements ISignalCommandMap {
     }
 
     public addMappingProcessor(handler: Function): ISignalCommandMap {
-        if (this._mappingProcessors.indexOf(handler) === -1)
+        if (this._mappingProcessors.indexOf(handler) === -1) {
             this._mappingProcessors.push(handler);
+        }
+
         return this;
     }