Documentation chapter "Defining a graph at instantiation-time" needs more details

[fonji]

Hello,

I was trying to work with a predicate that has data in multiple graphs.
I realized that not only "new" accepts the graph as a parameter, so does "find".
And then that giving an empty string as the graph's name will load the data from every graph (which is what I was looking for. Don't worry, it's for reading only).
Thanks for doing it like that, so I could find it out on my own.
I still think both of these points are worth a little note in readme.md. Would have spare me a couple hours, so I think it can help others.

[ricroberts]

Thanks. I know I need to update the readme and other docs. I'll try to revisit this soon.