Treat entire input as one parse context

You can now set OUTPUT FORMAT or TIME FORMAT and have it stick longer than to
the end of the line.

Also allow interactive remote sessions.  This get rids of the problem mentioned
in a10a2d4de; only a single top level statement is kept in memory at one time,
before it's executed and released.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
ca-shell: Added the -c/--command option

This option allows executing commands without having to go through the trouble
of sending the script to standard input.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>