AFNetworking/AFNetworking — pull request #337 by jparise (2012-05-15 00:08:57+00:00)
Title: Avoid appending empty form data parts

AFQueryStringComponentsFromKeyAndValue() always returns at least one
component (even if its *value* parameter is `nil`). If a component
doesn't have any form data, there's no need for us to append an empty,
nameless part to the multipart body.

Additional improvements to consider (which are not mutually exclusive
with this change):

- Don't run this loop at all when *parameters* is `nil`.
- Change AFQueryStringComponentsFromKeyAndValue() to return an empty
iterable when its *value* parameter is `nil`.

Also, remove the unused `kAFMultipartFormLineDelimiter` contant.