BServer/BApplication: added constructor for looper name.

* Added an extra looperName argument to the private BApplication
  constructor that BServer is using.
* This is now used to fix the ugliness that gave the registrar
  a different looper name, and even saves a string comparison.

headers/os/app/Application.h

@@ -101,6 +101,7 @@ private:
 	friend class BServer;
 
 								BApplication(const char* signature,
+									const char* looperName,
 									bool initGUI, status_t* error);
 								BApplication(uint32 signature);
 								BApplication(const BApplication&);