unbind call around free of sasl data.

Patch provided by John Morrissey <jwm@horde.net>

Use pres indices to support LE/GE [<=,>=] filters.

must be set later using dbenv_set_flags.

the patch from ITS#1289 to be ported here.

wrong length in statement selection (not critical); some cleanup (sizeof()-1 instead of strlen on constant strings)

moved rdn parsing in a dedicated routine, ldap_str2rdn(), that can be used directly; now ldap_rdn2str() handles all the formats

may need optimization;
uncomment #define USE_LDAP_DN_PARSING in libraries/libldap/getdn.c
to enable its use.
The ava/rdn/dn handling routines (append, insert, free and so) must
be made available thru declaration in some header.

enhanced dn parsing; see libraries/libldap/dntest for a 'demo'. Need to define USE_LDAP_DN_PARSING to override usual ldap_dn2ufn and so, and PARSE_UTF8 to parse attribute values as utf-8

Includes rewriting of URLs where the DN of the referral object
and the DN of the ref attribute attribute are not the same.
Also, always returns explicit DN and scope.
Currently, back-ldbm only.  Needs to be ported to back-bdb.