Routing should support HTTP OPTIONS

I can see no reason why a route like this should not be supported, as OPTIONS is a meaningful and useful verb:

map.connect '/orders/', :controller => "orders", :action => 'options', :conditions => { :method => :options }

but it raises an exception:

validate_route_conditions': Invalid HTTP method specified in route conditions

An easy fix seems to be to change ActionController::Routing::HTTP_METHODS to include :options (as in fact the almost identical ActionController::Request::HTTP_METHODS does).