Bug fixes and minor improvements
- Toggle att type had no default
- Nested children shortcodes weren't getting parent's global attributes
- Multi-selectbox wasn't properly returning values
- Dynamically populated attributes AJAX calls were asynchronous and intermittent
- Minor visual issue with multi-selectbox select / deselect all
- Modal output labels bug
- Reference to self in closure causing fatal error on some sights
- Temporarily disable undo render prevention due to possible bug (edit post page hangs)