protocol: Define Content Update behavior
The protocol currently is in a state where we define that commits create content updates and they are queued up until they are applied, and the old view that commit applies the state or caches it in the parent state.
This commit moves the protocol completely to the new model which retains the old behavior when no constraints are being used but allows for constraints to be used to hold back a group of synchronized content updates.
To convince yourself that this indeed retains the original behavior I suggest to play around with a few examples and look at the resulting graphs, as is done here:
Edited by Sebastian Wick