http: a non-curl_multi interface?

HI,

there's been several complaints about how git uses curl, particularly how it forces one to use curl's multi interface, so I've tried my hand at implementing a curl interface that doesn't need curl_multi.

This would allow git to work without curl_multi.

The non-curl_multi set of functions are done, and I've also taught push and http-push --persistent, to force git to behave as though USE_CURL_MULTI isn't defined.

Do you guys think this would bring any benefits, apart from requiring the user to use a curl library with the multi interface? Based on what I read in the docs, this would mean less open/closed connections, minimized credential prompting (if authentication is required), more backward compatibility, but it would also mean a possible performance degradation in git, since all http requests are sequential.

-- Cheers, Ray Chuan