rename conntype preference to backend

res/xml/preferences.xml

@@ -90,7 +90,7 @@
 	android:title="@string/p__connection">
 
         <ListPreference
-                android:key="conntype"
+                android:key="backend"
 		android:title="@string/p_conntype"
 		android:summary="@string/p_conntype_summary"
                 android:entries="@array/p_conntype_e"

src/backend/Backend.scala

@@ -27,7 +27,7 @@ object Backend {
 		)
 
 	def defaultBackendInfo(prefs : SharedPreferences) : BackendInfo = {
-		backend_collection.get(prefs.getString("conntype", "")) match {
+		backend_collection.get(prefs.getString("backend", "")) match {
 		case Some(bi) => bi
 		case None => backend_collection("tcp")
 		}