The "accept feedback from others" release.

• Add MessagePack serialization template from Phil Rodrigues.
• Add high level otypes functions from ddrepl / Alessandro Thea.
• Fix support for cross-schema referencing (Ale reports).
• Enrich template environment with some functions and filters.
• Support more of JSON Schema classes (xxxOf).
• Simplifiy "omodel" (breaking any existing users).
• Move shell-level testing to run under BATS.
• Flesh out otypes documentation.
• Improve validation command interface.
• Various other bug fixes, documentation improvements.