Change to pass in a UserDict as `state` to validator.

FormEncode's Schema sets attributes on the state object, and previously
passing in a Request object just happened to work with that, but this is
the correct way. Not to mention other validators may need to be passed
other values through state too.
Add tests for Equals validator.
Switch to using dummy object() for request.

With new implementation, the csrf token check should never be reached
(and so request never needed) if the honeypot is filled in.
Remove test that no longer applies.

now that CSRF token check isn't reached if honeypot check fails.
Remove schemas.py and tests.

Schemas for POST are moved into POST.py.
Rename validation package and validators module.

validation -> validation_and_conversion
validators -> validators_and_converters
Update imports.
Change to expect request under state["request"].
Rearrange and improve comments.
Add Equals validator.
Add validate_and_process_POST() and its tests.