Bytea/Base64 encoders for libpq - interested?

Hi!

Please find attached some very simple encoders/decoders for bytea and base64.
Bytea encoder is very picky about what it leaves unescaped - basically the
base64
char set ;-)

Since this seems to be a very poorly documented but much asked-for thing, I
thought
you would maybe like to add this code to libpq (so that everyone benefits).

I'm aware that function renames might be necessary, though.
If you like, I could make the code fit into libpq, and send diffs.

Any comments/interests?

Greetings,
Joerg