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/viewsettings/viewsettings.js

@@ -29,7 +29,7 @@ define(['require', 'dialogHelper', 'loading', 'apphost', 'layoutManager', 'conne
         }
 
         userSettings.set(settingsKey + '-imageType', context.querySelector('.selectImageType').value);
-   }
+    }
 
     function centerFocus(elem, horiz, on) {
         require(['scrollHelper'], function (scrollHelper) {