Add f-droid and google play badge to README

Author: tom-anders

README.md

@@ -1,4 +1,12 @@
 # Easy xkcd
+
+[<img src="https://fdroid.gitlab.io/artwork/badge/get-it-on.png"
+    alt="Get it on F-Droid"
+    height="80">](https://f-droid.org/packages/de.tap.easy_xkcd)
+[<img src="https://play.google.com/intl/en_us/badges/static/images/badges/en_badge_web_generic.png"
+    alt="Get it on Google Play" 
+    height="80">](https://play.google.com/store/apps/details?id=de.tap.easy_xkcd&hl=de&gl=US&pcampaignid=pcampaignidMKT-Other-global-all-co-prtnr-py-PartBadge-Mar2515-1)
+
 A beautiful, fast, and easy to use [xkcd](http://xkcd.com/) reader for Android.
 
 ### Features
@@ -22,4 +30,6 @@ Easy xkcd is available to download from either
 * [F-Droid](https://f-droid.org/repository/browse/?fdid=de.tap.easy_xkcd).
 
 ### Licenses
-Easy xkcd is licensed under the [Apache License v2](https://github.com/Foggalong/Easy_xkcd/blob/master/LICENSE). xkcd is licensed under a [Creative Commons Attribution-NonCommercial 2.5 License](http://creativecommons.org/licenses/by-nc/2.5/).
+- Easy xkcd is licensed under the [Apache License v2](https://github.com/Foggalong/Easy_xkcd/blob/master/LICENSE). 
+- xkcd is licensed under a [Creative Commons Attribution-NonCommercial 2.5 License](http://creativecommons.org/licenses/by-nc/2.5/).
+- Google Play and the Google Play logo are trademarks of Google LLC.