Remove globals, change conditional compilation, doormat

src/httpserver.cpp

@@ -1,3 +1,4 @@
+#ifdef PANDA3DS_ENABLE_HTTP_SERVER
 #include "httpserver.hpp"
 
 #include <vector>
@@ -97,4 +98,6 @@ void HttpServer::startHttpServer() {
 		server.listen("localhost", 1234);
 	});
 	http_thread.detach();
-}
+}
+
+#endif  // PANDA3DS_ENABLE_HTTP_SERVER