The `models<>` machinery added unnecessary complexity for little benefit.
Also, this makes Hana's concepts syntactically closer to concepts lite,
which should contribute to making them easier to grasp at first sight.
- 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
This (large) commit introduces the following changes:
- Each algorithm lives in its own header
- The concepts are defined in the concept/ subdirectory. They define the
`models` metafunction, some explicit default implementations (like
Applicative::transform_impl), and they include all the algorithms
related to that concept.
- Removed the `until` method from Logical
- Removed the `drop_until` method from Iterable
- [minor] Added the detail::nested_to utility
Closes#160
