* Non-fungible token traits

* Docs

* Fixes

* Implement non-fungible trait for Uniques

* Update frame/uniques/src/impl_nonfungibles.rs

Co-authored-by: Shawn Tabrizi <[email protected]>

* Update frame/uniques/src/impl_nonfungibles.rs

Co-authored-by: Shawn Tabrizi <[email protected]>

Co-authored-by: Shawn Tabrizi <[email protected]>