partial conversion to 1.12.4
urrg
Merge branch 'master' into v1.12.4
finishing v1.12.x support
docs for new/changed commands
redux of type system. adding an is-all type checker, which encapsulates any term that has runtime typing (indeterminate). all other types (except stream) extend this now.
adding date support
version bump! 1.12.x support + dates