- Allow specializing models_impl with a forward declaration only
- Modularize remaining concept headers
- Include <boost/hana.hpp> in unit tests to ease the transition
- Add the core/dispatch.hpp header to reduce the number of boilerplate includes
- Rename fold{l,r,l1,r1} to fold.{right,left} with overloads.
- Rename foldlM/foldrM to monadic_fold.{left,right}
- Add no-state variants of the monadic folds
- Improve the fold's documentation
- Deprecate the previous folds; they'll be removed soon
Fixes#18.
