Fix #78: Fail if a case class extends js.Any
Fix #83: swallow Unit expr when converting to js.Undefined.
Merge pull request #85 from sjrd/fix/issue83

Fix #83: swallow Unit expr when converting to js.Undefined.
Fix #79: Fail if an anonymous class extends js.Any
Merge pull request #86 from gzm0/topic/jsAny-restrictions-2.10

js.Any hierarchy & nesting restrictions (2.10)