* Makefile.am (EXTRA_DIST): Added aproxy.rb.

* COMPILE (riece-scripts): Added "aproxy.rb".

* riece-async.el (riece-async-buffer-size): Renamed from
riece-async-max-buffer-size.
(riece-async-backup-file): New user option.
(riece-async-server-program): New variable.
(riece-async-server-program-arguments): New variable.
(riece-async-open-network-stream): Use aproxy.rb.

* aproxy.rb: New file.