Cleanups of quoting details in the searches.

Cleanups of quoting details in the searches.
This fixes, among other thing, SF bug #456863.

Depending on the backend searches for pages and/or page names
containing '/', '\', '%', and/or '_' all failed in some way
or another.

The fixes to lib/dbmlib.php are untested, but parallel those in
lib/dbalib.php, so should be okay.

The fixes in lib/pgsql.php, lib/msql.php, and lib/mssql.php are
also untested.  They more or less parallel tested fixes in
lib/mysql.php, but it would probably be good if someone could
test them.

git-svn-id: svn://svn.code.sf.net/p/phpwiki/code/branches/release-1_2-branch@608 96ab9672-09ca-45d6-a79d-3d69d39ca109