Improve obfsproxy documentation
Some steps to improve obfsproxy's documentation:
Refactor README. Drop 'doc/THREAT_MODEL_PHILOSOPHICAL'. Improve 'doc/tor-obfs-howto.txt'.
Some steps to improve obfsproxy's documentation:
Refactor README. Drop 'doc/THREAT_MODEL_PHILOSOPHICAL'. Improve 'doc/tor-obfs-howto.txt'.