(WIP) Webserver: namespace-import @darkain's rewrite

[d-a-v]

Webserver:
import @darkain's Webserver rewrite from https://github.com/cosplaylighting/Arduino
+update host emulation

To try this new webserver,
uncomment USING_NEW_WEBSERVER in libraries/ESP8266WebServer/src/ESP8266WebServer.h

#include "ESP8266WebServerLegacy.h"
#include "ESP8266WebServerNew.h"

//#define USING_NEW_WEBSERVER

#ifdef USING_NEW_WEBSERVER
using namespace WebServerDarkain;
#else
using namespace WebServerLegacy;
#endif