Feature/httpd (#94)

* Stub code for http server

* can send a response, cannot process body yet

* write headers to the response

* remove commented code

* add simple test + set default http handler

* tweak CI + unittest

* add missing file

* rewrite http::trim in a simple way

* doc

ixwebsocket/IXWebSocketHandshake.h

@@ -64,8 +64,6 @@ namespace ix
         // Parse HTTP headers
         WebSocketInitResult sendErrorResponse(int code, const std::string& reason);
 
-        std::tuple<std::string, std::string, std::string> parseRequestLine(const std::string& line);
-        std::string trim(const std::string& str);
         bool insensitiveStringCompare(const std::string& a, const std::string& b);
 
         std::atomic<bool>& _requestInitCancellation;