Add reques_options argument to each http request

Hi

I needed to pass some arguments to the aiohttp request (i.e.: http basic auth), which is supported at the Resource level but not at the Attachment/Document/... level.
This patch adds that, on each public method (except the ones i missed, i guess ;) )

I think it would be best to be able to set that this on the Server object and propagate it to the objects returned, but i don't really have the time to implement that, so here's an intermediate solution.

What do you think?