Added About the App fragment, used libraries info, their licences and authors mentions

app/src/main/res/menu/drawer_menu.xml

@@ -1,4 +1,23 @@
 <?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Look4Sat. Amateur radio & weather satellites passes calculator for Android.
+  ~ Copyright (C) 2019, 2020 Arty Bishop (bishop.arty@gmail.com)
+  ~
+  ~ This program is free software; you can redistribute it and/or modify
+  ~ it under the terms of the GNU General Public License as published by
+  ~ the Free Software Foundation; either version 2 of the License, or
+  ~ (at your option) any later version.
+  ~
+  ~ This program is distributed in the hope that it will be useful,
+  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
+  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  ~ GNU General Public License for more details.
+  ~
+  ~ You should have received a copy of the GNU General Public License along
+  ~ with this program; if not, write to the Free Software Foundation, Inc.,
+  ~ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+  -->
+
 <menu xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     tools:showIn="navigation_view">
@@ -20,9 +39,5 @@
             android:id="@+id/nav_about"
             android:icon="@drawable/ic_about"
             android:title="@string/menu_about" />
-        <item
-            android:id="@+id/nav_credits"
-            android:icon="@drawable/ic_credits"
-            android:title="@string/menu_credits" />
     </group>
 </menu>