BindList with callback

[g105b]

This might be a way to simplify the sometimes confusing distinction between bindList and bindNestedList.

If bindList was made to be simple-data-only, bindNestedList could be deprecated completely to keep things simple, and a new bindListCallback could be introduced.

This will allow a callback function to be used to bind a nested list, with preconfigured context of the current node - increasing flexibility and making everything a lot more understandable.

[g105b]

I think this is obsolete with the v2 release. After release, I'll come back and close if appropriate.

[g105b]

Duplicated by #261