Always render async. Simplify bindings.
Improve render routine. Notify global binding listeners first.
Add Mixin.addBindingListener method.
Changes descriptor corrections. Mixin.addBindingListener only fires callback when value / meta value were changed.
Do not notify listeners if binding / meta binding value is not changed.
Notify listeners on meta-meta-binding changes.
Support optional subpath in Binding.meta.
Test Mixin.addBindingListener.
Return listener id from Mixin.addBindingListener.
Enable RAF rendering by default.
Update doc.