Fix issue #147.
If all proxies are in DOWN_STATE or BUSY_STATE state, select_proxy will run
forever in an infinite loop. When all proxies are not available, we wait some
intervals and retry. The wait time starts with 10 milliseconds and is
increased by 10 milliiseconds in each loop. 14 loops sums up with 1.05 second.
accept proper RFC1929 auth subnegotiation version field
this was wrongly fixed in 06c20ed394a65cc9e959a30ea74b8b256f76c1fa
instead of reverting we now accept the correct version
(version field containing 1) plus the incorrect version (5) given by some
proxyservers in the wild. curl accepts both forms too.
solaris curiously defines connect to point to __xnet_connect when
_XOPEN_SOURCE is defined 600.
that means some programs use the real connect symbol, while others
use __xnet_connect.