Added new 'autolocal' redirect-gateway flag. When enabled, the OpenVPN

Added new 'autolocal' redirect-gateway flag.  When enabled, the OpenVPN
client will examine the routing table and determine whether (a) the
OpenVPN server is reachable via a locally connected interface, or (b)
traffic to the server must be forwarded through the default router.
Only add a special bypass route for the OpenVPN server if (b) is true.
If (a) is true, behave as if the 'local' flag is specified, and do not
add a bypass route.

The new 'autolocal' flag depends on the non-portable test_local_addr()
function in route.c, which is currently only implemented for Windows.
The 'autolocal' flag will act as a no-op on platforms that have not
yet defined a test_local_addr() function.

Increased TLS_CHANNEL_BUF_SIZE to 2048 from 1024 (this will allow for
more option content to be pushed from server to client).

Raised D_MULTI_DROPPED debug level to 4 from 3.

Version 2.1_rc16b.

git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@4446 e7ae566f-a301-0410-adde-c780ea21d3b5