Merge 'syb_connected' into 'trunk'

r5859@hlagh (orig r6912):  caelum | 2009-07-01 06:21:30 -0700
new connected() for dbd::sybase users
r5860@hlagh (orig r6913):  caelum | 2009-07-01 06:25:46 -0700
add a couple of dbd::sybase reconnection tests
r5861@hlagh (orig r6914):  caelum | 2009-07-01 06:35:07 -0700
better connection test
r5862@hlagh (orig r6915):  caelum | 2009-07-01 06:45:05 -0700
use dbh->do for connected instead of prepare_cached
r5863@hlagh (orig r6916):  ribasushi | 2009-07-01 06:55:21 -0700
Segfault
r5864@hlagh (orig r6917):  caelum | 2009-07-01 07:03:22 -0700
use ->do instead of ->prepare_cached in oracle's connected() too
r5865@hlagh (orig r6918):  caelum | 2009-07-01 08:20:52 -0700
fix segfault with old DBD::Sybase
r5866@hlagh (orig r6919):  caelum | 2009-07-01 08:39:18 -0700
move connection tests into _ping()