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

ws/ws.h

@@ -93,4 +93,6 @@ namespace ix
                       const std::string& redisPassword,
                       bool verbose,
                       const std::string& appsConfigPath);
+
+    int ws_httpd_main(int port, const std::string& hostname);
 } // namespace ix