Proxygen: Facebook's C++ HTTP Libraries

This project comprises the core C++ HTTP abstractions used at Facebook.
Internally, it is used as the basis for building many HTTP servers,
proxies, and clients. This release focuses on the common HTTP
abstractions and our simple HTTPServer framework. Future releases will
provide simple client APIs as well. The framework supports HTTP/1.1,
SPDY/3, SPDY/3.1, and HTTP/2. The goal is to provide a simple,
performant, and modern C++ HTTP library.