* riece-rdcc.el: Bind temporary-file-directory.

* riece-rdcc.el: Bind temporary-file-directory.
(riece-rdcc-send-program): Allow block-size to be controlled from
elisp.
(riece-rdcc-block-size): New user option.
(riece-rdcc-temp-file): New variable.
(riece-rdcc-received-size): New variable.
(riece-rdcc-filter): Don't keep received bytes in the process
buffer; use riece-rdcc-format-size to display progress.
(riece-command-dcc-receive): Create a temporary directory which
holds a received file.