xhr made cancelable in Lwt_obrowser
xhr made cancelable in Lwt_obrowser

Ignore-this: bed8390fff2479658d1a400495275a0a

darcs-hash:20100628121109-8ea92-d15911965654b6f207eb3cfb4308098d339324f6

mfp/ocsigenserver,mfp/ocsigenserver