Update README.md

Author: christophwille

README.md

@@ -1,4 +1,19 @@
-AvalonEdit
-==========
+# AvalonEdit
+
+AvalonEdit is the name of the WPF-based text editor in SharpDevelop 4.x "Mirador" and beyond.
+
+[avalonedit.net](http://avalonedit.net/)
+
+
+Downloads
+-------
+
+AvalonEdit is available as [NuGet package](https://www.nuget.org/packages/AvalonEdit). Usage details, documentation and more
+can be found on the [AvalonEdit homepage](http://avalonedit.net/)
+
+
+License
+-------
+
+AvalonEdit is distributed under the [MIT License](http://opensource.org/licenses/MIT).
 
-AvalonEdit is the name of the new WPF-based text editor in SharpDevelop 4.x "Mirador".