Add some linting rules for the CI (#587)

* enable one-var rule

* enable indent rule

* enable no-multiple-empty-lines rule

* enable no-empty rule

* enable no-trailing-spaces rule

* enable no-extra-semi rule

* add eslint rules to fix block spacing

* enable max-statements-per-line rule

* enable brace-style rule

* fix some spacing issues and add future rules

* add code suggestions

src/components/lazyloader/lazyloader-intersectionobserver.js

@@ -45,7 +45,7 @@ define(['require', 'browser'], function (require, browser) {
                 }
             }
         },
-            observerOptions
+        observerOptions
         );
 
         this.observer = observer;