Major Changes

• Make websockify properly terminate children on SIGTERM (#226)
• Remove logging in signal handlers (this can cause Python to hang under certain conditions) (#219)
• Make it easier to log to a file (#205)
• Add support for IPv6 addresses in tokens in the TokenFile token plugins (#197)
• Improve auth plugin framework to enable better support for HTTP auth (#194, #201)
• Fix bug in JSONTokenAPI token plugin (#192)
• Fix a missing variable in the exception handler (#178)