Modified the UI of Settings. also shows any previously saved settings

1-> user defined node options open up directly below the check box if it is checked, and closes it if unchecked
2->automatically shows the previously saved user defined settings if any
3->fixed crash on settings activity
4->DhtNode.port != null was causing indexoutofboundexception if nothing was downloaded
5->dhtdialogfragment.java file not needed now, can be removed