Changelog for isomorphism-class-0.3.1

0.3

Extracted the Is and IsSome typeclasses into a separate library "lawful-conversions"
Restored the IsomorphicTo typeclass from the 0.1 design without restoring the String instance and the showAs utility

IsomorphicTo renamed to Is
IsSome is introduced as a parent class to it
to moved to IsSome
showAs dropped
String isomorphism instances for textual types dropped, since they were not exactly isomorphisms
IsSome instances added for String for textual types