X11 forwarding over an SSH channel. If a passphrase is required when doing a
pwmd_open() or pwmd_save(), the remote pinentry would be able to use the local
DISPLAY.

Language bindings for perl, python and other languages would be nice.

A passphrase with an SSH identity file. Need upstream libssh2 (1.2) support.

pwmd_cancel(): It can be done in an inquire already by returning
GPG_ERR_CANCELED from the inquire callback. For receiving data it's a
different story because of how the client connects to the server. You'll
notice in the pwmd log that the command completes before all of the data is
actually sent (especially over SSH). I think this is do to buffering of the
pwmd socket. So when you do a GET with a lot of data then try to cancel it,
the server thinks the command already completed. The buffered data cannot be
ignored from the client since its waiting to be read from the UDS via the
proxy command (socat) over SSH. I've read that to do unbuffered IO I'd need to
setup a PTY in raw mode (stdio from the proxy command).

SSH keepalives in pwmd_process()?

Remove all of the async functions. They are useless because libassuan blocks
during commands. Or hack libassuan to do non-blocking? May as well just use
threads.
