build_request: we don't need "tname" here
raw_call: generate _source_method only for GET requests
update required OAuth version to 0.0.5
check_args: add support for checking a specific type

- the rule can be a table instead of a boolean, with format: { <required>, "type" }
implement the "statuses/update_with_media" API method

- this uses the recently added multipart support in the OAuth library
updated examples/tweet.lua

- now it can upload images using tweet_with_media