monitors: Made from_rect nonmember, nonfriend.
vec_set: Added.

vec_set is just a multiindex container that works as a vector and a set.
Containers of oth monitors and clients require sequence and unique
associative semantics. vec_set implements this for both.
monitors: Implemented in terms of vec_set.
monitors, vec-set: Moved test modules to start refactor.
vec-set: Renamed test module files.
monitors: Bashed superfluous includes.
vec_set: Rename pass.
vec_set: Added val_t alias.
vec_set: Decoupled tests from monitor.
list-set: Renamed vec-set to list-set.
list-set: Renamed unit test dir.
list-set: Renamed vec_set.* to list-set.*.
list-set: Propagated name change through code.
list-set: Changed semantics from vec to list.
list-set: s/vec/list throughout.
monitors: Fixed include order.
Line wrapping pass.
clients: next-is-sequential.
clients: next-is-cyclic.
clients: Refactored next fixture into own module.