on SCCs (closes #16).

find_idempotence(): Replace fixed point iteration with a check based

on SCCs (closes #16).

See merge request !66

topological order, chunked according to SCCs of the dependency graph.

See also #15.

be faster in the common case (all the types are the same).

which causes a TypeError (closes #14).

Improve pickleability: Avoid interning instruction ids that are None,

which causes a TypeError (closes #14).

See merge request !69

Fix dependency graph drawing for {Call,ReturnFrom}Kernel

See merge request !70

Fix atomicity check

See merge request !71

Faster type inference

See merge request !68

Fix barrier insertion above top of loop (Fixes #17 on gitlab)

See merge request !73