nit! comments
initial _make_delegation_method() wrapping

...to allow us to generate custom accessors a la native traits:

    handles => {

        method_name => sub { ... accessor body (value in $_) ... }
    },

sooooooooooooooooo lazy.
....or this.  hm.
...or with additional helper coderefs?
Nope, let's do it plain. let people construct their own bits.

No custom coderefs created or passed to custom accessors now; let people do
what they need to do on their own.

The attribute metaclass is stashed in $_, and we've provided 3 convenience
methods to help interact with the associated class' meta-instance class.
Document: handles => { foo => sub { ... } }

etc.
Add basic handles/coderef tests