Add ContextPropertySetter to set a data property value directly from the UI

[Christian Oeing]

Right now it always requires a Command to change a context from the UI. This is okay as in a real application the UI actions are passed to the game logic and the logic then changes the context(s) if the action was valid. But for testing or prototyping it may be helpful to have such a direct way to change a context.

[Christian Oeing]

There is a ContextDataUpdater now which keeps a context data node up-to-date with a specified DataProvider. This may be a class to consider.

It might still be a command which takes a path to the data that should be set and is invoked with the data to set as an argument (or the data provider is set as well).

[Christian Oeing]

ContextDataUpdateCommand would be a good name for the command

[Christian Oeing]

There are Synchronizers now which are an easy way to synchronize the value of a UI control and a context data node