trojan 1.10.1

Changelog

• Fix fd leak (#60).
• Gracefully handle too many open files (#60).
• Fix a bug that causes trojan to crash if the connection is terminated before a session is established.
• Cancel async tasks when stopping the service.
• Change some fatal level logs to warn (#59).
• Log received signal number.
• Add android log facility.
• Refer to basic_stream_socket instead of basic_socket in SSL sockets.
• Update Boost version in AppVeyor.