Remove invalid autoload statement.

`Have` has been moved into the rspec-collection_matchers gem.
Use `===` rather than `==` as an alias for `matches?`.

`===` (used for case-statement category-matching)
is a better fit for the semantics of an RSpec matcher.

`===` is not meant to be symmetric, but `==` is.
Private APIs should not come first.
Move built in matcher specs under built_in dir.

This mirrors the lib directory structure and helps
differentiate the specs that aren't for specific
matchers.