Make IO of data for preferences more robust

Never write to preferences if running in console mode
Delete stale settings lock files

On Linux, application settings are stored in a text file in the users home folder. On Windows, these settings are stored in Registry. Users have reported stale lock files the configuration directory. In some cases, these lock files can prevent the application from starting. It appears that the application start, but no GUI is displayed.

ApplicationExeCode/RiaMain.cpp

@@ -78,6 +78,8 @@ int main( int argc, char* argv[] )
     }
 #endif
 
+    RiaMainTools::deleteStaleSettingsLockFiles();
+
     // The Qt::AA_ShareOpenGLContexts setting is needed when we have multiple viz widgets in flight
     // and we have a setup where these widgets belong to different top-level windows, or end up
     // belonging to different top-level windows through re-parenting.