Add feature to fix link drag&drop in CC

This change adds an option to fix the drag&drop bug that exists in
CKEditor (https://dev.ckeditor.com/ticket/13569), which is the library
used for the rich text editor in the Community Console.

Fixes: #20
Change-Id: Ic82bf6ee6d583876858f21291723dacb5e74debe
diff --git a/src/options.css b/src/options.css
index 2ee205f..e754e14 100644
--- a/src/options.css
+++ b/src/options.css
@@ -20,3 +20,7 @@
   margin-bottom: 16px;
   color: green;
 }
+
+[hidden] {
+  display: none;
+}