Encode a type in the owner for enhancement drivers

[yacovm]

In case some user would want to implement an enhanced driver which gives additional capabilities to tokens of existing drivers, where only some tokens can be used for the enhanced capabilities, then the system might reach a state where two or more encoding schemes coexist: (a) The fabtoken token encoding and (b) The encoding for the enhanced token.

In such a setting, we need a way to distinguish between the two encoding schemes.

Therefore it may make sense to encode a Type in some field (such as the owner) to mark that the token needs to be parsed in one scheme and not in another.