pgbouncer - pgbouncer: new features to SBuf - struct field reorder to

Log Message:
-----------
new features to SBuf

- struct field reorder to get aligned buffer
- support rewriting pkt header
- support listening for full pkt data
- clean some comments

Modified Files:
--------------
pgbouncer/include:
bouncer.h (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/bouncer.h.diff?r1=1.4&r2=1.5)
sbuf.h (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/sbuf.h.diff?r1=1.2&r2=1.3)
pgbouncer/src:
client.c (r1.17 -> r1.18)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/client.c.diff?r1=1.17&r2=1.18)
objects.c (r1.31 -> r1.32)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/objects.c.diff?r1=1.31&r2=1.32)
sbuf.c (r1.18 -> r1.19)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/sbuf.c.diff?r1=1.18&r2=1.19)
server.c (r1.19 -> r1.20)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/server.c.diff?r1=1.19&r2=1.20)