1.0.0.0

[re-xyr]

I'm unsure if I'd have the time, but a potential 1.0 should:

1. minimize unsoundness; Unlikely but possible segfaults #15 should be done away with
2. have inference friendly API variants (Adding inference-friendly functions #20)
3. decide what to do with replace i.e. toEffWith (Scoped effects is broken #5, Semantics of interpose #19). It's supposedly nice to have this semantics, but this is dubious:
   1. we haven't come up with any kind of (half-)formal semantics for it
   2. this problem isn't known to arise in any practical use cases