- Rename elem to contains
- Rename subset to is_subset, and make is_subset applicable in infix notation
- Add the at_key method
- operator[] is now bound to at_key instead of find
- Make decltype_ the identity on Types
- Add the alignof_ function
- Allow sizeof_ to work with non-Types
- Remove the trait_ helper
- Allow Metafunctions to be called with non-Types
- Add make<Type>, which is equivalent to decltype_
- Split type class instances into separate files
- Instances provided automatically by a type class are actually MCDs
- Test each instance in a single file, not one file per method
- Refactor the operator system to fix the ADL-related bug.
