clean up detection and handling of drivers with problematic AA lines

only draw topmost screen if topmost screen isn't transparent (speeds up options menus in editor)
optimized beat bar drawing in NoteField

stepmania/src/arch/InputHandler/InputHandler_Win32_Pump.cpp

@@ -172,7 +172,8 @@ int InputHandler_Win32_Pump::dev_t::GetPadEvent()
 		return -1;
 
     if(ret == 0) {
-		LOG->Warn(werr_ssprintf(GetLastError(), "Error reading Pump pad"));
+		// this prints too much info in Win98
+//		LOG->Warn(werr_ssprintf(GetLastError(), "Error reading Pump pad"));
 	    return -1;
     }