Merge changes made in Gnus trunk.

Merge changes made in Gnus trunk.

nnimap.el (nnimap-request-group): Use the stored info for the dont-check case.
nnimap.el: Use deffoo instead of defun for interface functions.
gnus-int.el (gnus-request-group): Take an optional `info' parameter.
nnimap.el: Allow nnimap-request-group to do a complete marks sync on `M-g'.
nnimap.el: Get credentials for numerical equivalents of the port numbers.
gnus-html.el (gnus-html-wash-tags): Add support for i, b and u HTML tags.
nnimap.el (nnimap-update-info): Extend the info so that we can set the marks.
nnimap.el (nnimap-open-connection): Fix typo -- should be 'shell, not 'stream.
nnimap.el: Allow PREAUTH nnimap connections to log in without credentials.
nnimap.el (nnimap-update-info): Fix off-by-one error when concatenating ranges when doing a partial update.
gnus-html.el (gnus-html-schedule-image-fetching): Use `url' rather than curl to retrieve images.
nnimap.el (nnimap-update-info): When doing partial marks update, get the range update right.
nnimap.el (nnimap-wait-for-response): Be a bit more lax in finding the end of the command we're looking for.
nnimap.el: Allow sending \n instead of \r\n on 'shell streams.
gnus-html.el (gnus-html-schedule-image-fetching): Fetch all images in parallel.