effect.Resource instance for A <: java.io.Closeable
fixed checkGenTypeClasses, i think
Compile scalaz with -Yno-generic-signatures

Scalaz artifacts did not pass the ASM verifier. See SI-7932 for the
underlying issue.

Fixes #571
Merge pull request #638 from tpolecat/resource

effect.Resource for subtypes of java.io.Closeable
deprecate `EphemeralStream#head` and `#tail`

Those methods are unsafe. Since they are used for internal implementation,
they will become private after the deprecation cycle.