- update: Bootstrap version to v4.0.0-beta.2

- update: vue-chartjs version to 3.0.0
- refactor: Remove old SCSS variables
- refactor: Breadcrumb Menu styles
- fix: External links issue
- fix: Mobile sidebar-nav height issue

Vue_Starter/scss/bootstrap/mixins/_screen-reader.scss

@@ -1,7 +1,7 @@
 // Only display content to screen readers
 //
-// See: http://a11yproject.com/posts/how-to-hide-content
-// See: http://hugogiraudel.com/2016/10/13/css-hide-and-seek/
+// See: http://a11yproject.com/posts/how-to-hide-content/
+// See: https://hugogiraudel.com/2016/10/13/css-hide-and-seek/
 
 @mixin sr-only {
   position: absolute;