Make GroovePlayer a singleton to avoid being created for each browser. Add login UI component to eventually hold landing screen. Actually start server with initial interface.

src/WebInterface.h

@@ -21,9 +21,16 @@
 #define WEBINTERFACE_H
 
 #include <Wt/WApplication>
+#include "GroovePlayer.h"
 
 class WebInterface : public Wt::WApplication
 {
+public:
+    WebInterface(const Wt::WEnvironment& env);
+    void loginCompleted();
+private:
+    struct internal;
+    internal* priv_int = 0;
 };
 
 #endif // WEBINTERFACE_H