fix of some issues with multi-line query editing

Fix of several issues:

1) Fix the problems with the \s command.
When the saveHistory is executed by the \s command we must not do the
conversion \n -> \x01  (per
http://archives.postgresql.org/pgsql-hackers/2006-03/msg00317.php )

2) Fix the handling of Ctrl+C

Now when you do
wsdb=# select 'your long query here '
wsdb-#
and press afterwards the CtrlC the line "select 'your long query here '"
will be in the history

(partly per
http://archives.postgresql.org/pgsql-hackers/2006-03/msg00297.php )

3) Fix the handling of commands with not closed brackets, quotes, double
quotes. (now those commands are not splitted in parts...)

4) Fix the behaviour when SINGLELINE mode is used. (before it was almost
broken ;(

Regards,
    Sergey

*****************************************************
Sergey E. Koposov
Max Planck Institute for Astronomy
Web: http://lnfm1.sai.msu.ru/~math
E-mail: math@sai.msu.ru