This removes all the hard-coded request headers from the requests module so
they can be overridden by user provided headers dict. Furthermore allow
streaming request data without chunk encoding in those cases where content
length is known but it's not desirable to load the whole content into
memory. Also some servers (e.g. nginx) reject HTTP/1.0 requests with the
Transfer-Encoding header set.
The change should be backwards compatible as long as the user hasn't
provided any of the previously hard-coded headers.
Signed-off-by: Mirza Kapetanovic <mirza.kapetanovic@gmail.com>
Mirza Kapetanovic