MOP-0.10 - A Meta Object Protocol for Perl 5

Changes for version 0.10 - 2017-10-20

ENHANCEMENT
- There is now a public API of utility functions in the MOP::Util module.
  - see the docs for more info
- added the MOP::Method::Attribute class to represent any attributes attached to a method.
  - see below for how this changes the `get_code_attributes` method within MOP::Method
!!!!BREAKING CHANGES!!!!
Roles
- role to class composition behavior has changed
  - there is now no difference in the way compositon beheaves when applied to a class or to a role
    - previously only classes complained if there was a conflict in the compositon process, now both roles and classes complain
    - previously only classes complained if there was a method requirement after composition was complete, now both roles and classes complain
MOP::Slot
- The `add_slot` method now will set the COMP_STASH of the initializer, therefore taking ownership of that CV, this mirrors what `add_method` does
  - this is actually unlikely to break much, but is significant, so maybe
- MOP::Slot objects no longer act as overloaded CODE refs (the &{} operator), this function is now the domain of the MOP::Slot::Initializer
- MOP::Slot::Initializer has completely changed, the last version should be ignored completely
  - the `builder` feature has been completely removed
  - all methods other than `new` have been removed
  - it is a blessed CODE reference
MOP::Method
- the API for `get_code_attributes` in MOP::Method has changed, it now returns MOP::Method::Attribute objects
DEPENDENCIES
- added Sub::Metadata, used to detect null CVs and mutate the COMP_STASH of CVs.
- added Devel::Hook, which is used in the new MOP::Util function `defer_until_UNITCHECK`
- bumped the UNIVERSAL::Object dependency version to make sure we have support for immutable CODE ref instances (needed for MOP::Slot::Initializer)