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/scripts/librarybrowser.js

@@ -156,7 +156,8 @@ define(["userSettings"], function (userSettings) {
                 html += '<h2 style="margin:0 0 .5em;">';
                 html += Globalize.translate("HeaderSortBy");
                 html += "</h2>";
-                var i, length;
+                var i;
+                var length;
                 var isChecked;
                 html += '<div>';
                 for (i = 0, length = options.items.length; i < length; i++) {