Check input array for uniqueness
`obj` property in object ns set
Reorder imports
Throw on add & delete set operations
`has` for object namespace set
`count` for object sets
Support undefined as compareFn for live lists
`compare` functions for base namespaces
Use string comparision for Base namespace
Rename set extensions meta property
Emit updates on indexes whenever index is altered
listByProperty for object namespaces

Additionally port setExtensions for further filters