Re: proposal: psql \setfileref

Hi

I am sending a initial implementation of psql content commands. This design
is reaction to Tom's objections against psql file ref variables. This
design is more cleaner, more explicit and more practical - import can be in
one step.

Now supported commands are:

r - read file without any modification
rq - read file, escape as literal and use outer quotes
rb - read binary file - transform to hex code string
rbq - read binary file, transform to hex code string and use outer quotes

Usage:

create table testt(a xml);
insert into test values( {rq /home/pavel/.local/share/rhythmbox/rhythmdb.xml}
);
\set xxx {r /home/pavel/.local/share/rhythmbox/rhythmdb.xml}

This patch is demo of this design - one part is redundant - I'll clean it
in next iteration.

Regards

Pavel