Add DataPair() Data Type to scripted plugins and custom attributes

[lightcube]

For writing custom attributes and scripted plugins, it would be nice if we could use the DataPair() class.

#dataPair

#dataPairTab

This would be very beneficial for arbitrary data storage where the data rules are generated (like storing data for game engine entities).

Currently to store this kind of data requires clunky workarounds like storing the data in strings and reparsing.