README: improve the look and some of the wording

README.md

@@ -1,5 +1,9 @@
-EteSync
-=======
+<p align="center">
+  <img width="120" src="app/src/main/res/mipmap/ic_launcher.png" />
+  <h1 align="center">EteSync - Secure Data Sync</h1>
+</p>
+
+Secure, end-to-end encrypted, and privacy respecting sync for your contacts, calendars and tasks sync client for Android.
 
 [<img src="https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png"
       alt="Get it on Google Play" 
@@ -11,14 +15,16 @@ EteSync
 ![GitHub tag](https://img.shields.io/github/tag/etesync/android.svg)
 [![Chat on freenode](https://img.shields.io/badge/irc.freenode.net-%23EteSync-blue.svg)](https://webchat.freenode.net/?channels=#etesync)
 
+# Overview
+
 Please see the [EteSync website](https://www.etesync.com) for more information.
 
 EteSync is licensed under the [GPLv3 License](LICENSE).
 
-EteSync's source code was originally based on [DAVdroid](https://www.davx5.com) but the codebases has since diverged quite significantly.
+Third Party Code
+================
 
-Third Party Libraries
-=====================
+EteSync's source code was originally based on [DAVdroid](https://www.davx5.com) but the codebases has since diverged quite significantly.
 
 This project relies on many great third party libraries. Please take a look at the
 app's about menu for more information about them and their licenses.