multi interface not implemented

[iustin]

Hi,

Currently curl (Haskell) bindings only export the easy interface, but completely ignore the multi interface. Having that would allow a better use of curl in non-threaded environments, by actually doing the various requests in parallel (threaded use is blocked by issue #3 currently).

The usual way of using the multi interface is to build "regular" easy handles, and then register them with a "multi" handle; after that, there are two possibilities: select/wait on a set of sockets (as computed by curl itself) and use curl_multi_perform, or use curl_multi_socket_action which seems be a fancier interface. Not sure which way maps best for Haskell use, but reading just the C interface, multi_perform seems simpler.