Add FontAwesome 4.0 support
Convert to singleton
Add PHP version check.
Clarify PHP check logic
Rename frontend class to MSI_Frontend
Show icons in nav-menus.php
Add icons to newly created menu items
Fix icon-sign icons in 4.0
Add shortcut icons for auto-filling URL and Link Text
Move admin CSS to menu-social-icons-admin.css
Fix recursive JS call. Add fa-fw for 3.2.1.
Add admin screenshot
Update readme
Merge branch 'r/1.3'