- filter(), __update_upstream_query() when filter is a function, WIP on _update upstream query directly with downstream changes
- core tests: stop testing filter() with no downstream set() as filter() becomes truly lazy
- socket_io_crossover(): remove unused code
Merge branch 'master' of github.com:ConnectedSets/ConnectedSets
Merge branch 'master' of github.com:ConnectedSets/ConnectedSets