ref: f33e854ad65a4f7162967c10f6c4278a160cfcb3 dhall-ruby/bin d---------
Self-describe CBOR for Expression#to_binary

CBOR.encode(expression) and Expression#to_cbor remain untagged "standard
Dhall" but the default Expression#to_binary now always tags the output
with self-describe CBOR.  This is supported by the standard for decoding
the output will still be compatible with all compliant implementations,
and it makes the binary format easier to identify in the wild.
Initial dhall-compile script

Add to build that after tests pass we compile the whole Prelude
Allow Symbol in yaml-to-dhall
Add experimental json/yaml to dhall scripts