Add Realm#dup through initialize extension.
Rename a cucumber step to be more domain-oriented.
Factorize and refactor steps about representations.
Take realm as parameter in Syntax methods.
Add missing String in builtins.
Add support for default realm and use it implicitely in features.
Rename Realm as System and remove realm/schema distinction.
Rename Q/builtins as Q/default and add (date)time support.
Rewrite the README now that q-lang.io is available.
Add BuiltinType#include?
Add AdType#include?
Add UnionType#include?