[feature request] Support schema evolution

[MartinBrugnara]

Please consider adding support for schema evolution, i.e. modify the schema over time by adding new vertex or node labels. Closes #59.

The code developed for this feature may also help with automatic schema inference, see #57.

[arcanefoam]

After some brainstorming I think this is not possible to implement with the current architecture, and in a nutshell needs a separate code base to handle graph integrity (as we would need to use Anonymous Graphs ).

For this two work the driver needs a major overhaul in order to add code that provides graph integrity throughout. I would keep this as an enhancement request, but for the moment I don't have the time to make such a big change.