Added PostgreSQL 9 support.

See 1eccd.
Added pgsql.app.
Added the field vcard.server into pg schema. Fixed string escaping.
username text => username varchar(250). Fixed bytea hex-escaping.
Added pgsql to reltool.config.
Applied small optimizations in SQL escaping.

Moved the body of the functions ejabberd_odbc:escape/1 and ejabberd_odbc:escape_like/1
into odbc_queries.
Use binaries for ODBC queries. Added odbc_queries:update_set_t/3.
Deleted unused mysql:quote/1.
Improved mysql driver.

Rewrote asciz/1 using standard library functions.
Send a query as an iolist into a socket.
Replaced strings with binaries. Made bxor_binary/2 shorter.
Use binaries for attributes in ODBC.
Ignore apps/ejabberd/include/XmppAddr.hrl
Increased pool size (10 => 32) and message queue threshold (100 => 500).
Optimization: avoid temporary tables and filesort.
Changed the order of indexes in index hints.
Added functions for encoding/decoding JIDs stored using ODBC.
Minified JIDs.
Moved JID serialization functions into mod_mam_utils.
Fixed MySQL connection leakage with dedicated connections. Made dedicated connections truly dedicated (do not register them).
Add information about mod_mam_odbc_async_pool_writer into ejabberd.cfg.
Made index hints working with MySQL only.