Pulse 9.1R14: handle 0x2e20f000 main configuration packet

This handles the main configuration packet as seen on pulse 9.1R14. I was recently exposed to this version and found openconnect was failing with "Unexpected IF-T/TLS packet when expecting configuration".

The reason for the change of pulse version at all was to gain IPv6 support. Having looked at the two open issues for this error message (#58 (closed) and #98 (closed)) and finding the nc protocol does not support IPv6 I decided to take a look at the config packet I was receiving. I discovered that it's almost the same as the code expected, only starting 2e20f000 instead of 2c20f000 and with what appears to be an extra attributes header prepended to the routing info.

With this patch (combined with !330 (closed) and some hacky modifications to vpnc-script to handle an IPv6 VPNGATEWAY) I have functional split tunnel v4 + v6 and can establish the tunnel over either ipv4 or ipv6. I'm not sure if this is useful - I note that there are other MRs open that would conflict with this - please let me know, thanks!