Only call LateUpdate when it's necessary (for initialization) to avoid big number of calls when application is running

[Christian Oeing]

From the forum (https://forum.unity.com/threads/released-data-bind-for-unity.298471/page-6#post-3563009 and https://forum.unity.com/threads/released-data-bind-for-unity.298471/page-6#post-3515005):

"I have a pretty small scene and every frame I get 500+ calls to lateUpdate as I am using 100+ elems in scroll list with few bindings each. I would really appreciate it if you make a small fix to reduce the amount of LateUpdate calls."

[Christian Oeing]

Added a global initializer for the data context node connectors. This makes sure that only one LateUpdate is executed instead of one for each data context node connector (DataBinding, Command,...)