expose the fields metadata via OPTIONS as described in https://github.com/tomchristie/django-rest-framework/issues/192

missing:
 - get fields for method (currently all the same)
 - tests
 - right placement of code
Merge branch 'issue-192-expose-fields-for-options' of github.com:nschlemm/django-rest-framework into http_debug_error_page_doc
Added humanized field names and types