Demonstrate Population in the current examples

[chopfitzroy]

Case

Request.

Issue

The current examples do not demonstrate Population also the current documentation a little hard to follow (I am working on a PR but I am need to get my head around it more first) hence why an example may be productive.

[kethan]

What about array of reference? And nested population ?

[pubkey]

NOTE: I'm currently working on this. Fix comes soon