make MapAct startable

AndroidManifest.xml

@@ -22,7 +22,11 @@
         </activity>
         <activity android:name=".PrefsAct" android:label="@string/app_prefs" />
         <activity android:name=".MapAct" android:label="@string/app_map"
-		android:theme="@android:style/Theme.NoTitleBar" />
+		android:theme="@android:style/Theme.NoTitleBar" >
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+            </intent-filter>
+	</activity>
 	<service android:name=".AprsService">
 	    <intent-filter>
 		<action android:name="de.duenndns.aprsdroid.SERVICE" />