use field/1 to encode the multipart id
fix multipart
make sure we correctly handle chunked encoding when sending files
fix multipart encoding when sending a file
remove spurious logs
add support for partial file uploads

With this change you can now send only part of a file by setting from
where to start and the number of bytes to send. If the transport and the
OS support a zero-copy sent (using the sendfile API) will be used.
bump to 0.4.1
return received buffer when no content lenght is given (http 1.0)

- return the buffer and mark the response as done when the connection
  is closed when no content-lenght is given and the HTTP version is 1.0
- return the buffer on error closed in other cases:

    {error, {closed, Buffer}}

fix #21
fix indentation
add more doc for the new sendfile option
support partial file upload in multipart streams as well.
we are in 2013, let the license reflects it.
0.4.1 changes
bump expm info to 0.4.1
update doc
fix typo
Removed duplicate line about "chunked encoding support"
handle identity transfer encoding
bump to 0.4.2
bump expm package to 0.4.2 as well