libtorrent-rasterbar: updated to 1.2.6

1.2.6:
fix peer timeout logic
simplify proxy handling. A proxy now overrides listen_interfaces
fix issues when configured to use a non-default choking algorithm
fix issue in reading resume data
revert NXDOMAIN change from 1.2.4
don't open any listen sockets if listen_interfaces is empty or misconfigured
fix bug in auto disk cache size logic
fix issue with outgoing_interfaces setting, where bind() would be called twice
add build option to disable share-mode
support validation of HTTPS trackers
deprecate strict super seeding mode
make UPnP port-mapping lease duration configurable
deprecate the bittyrant choking algorithm
add build option to disable streaming

(adam)