Split out contributing information, update readme according

CONTRIBUTING.md

@@ -0,0 +1,12 @@
+# Contributing to WPF Designer
+
+Thanks for helping to improve the WPF Designer.
+
+In order for your changes to be accepted, please add the following statement to your pull request:
+
+_I certify that I own, and have sufficient rights to contribute, all source code and related material intended to be compiled or integrated with the source code for the WPF Designer open source product (the "Contribution"). My Contribution is licensed under the MIT License._
+
+Unless we have this statement in your pull request, we cannot accept it.
+
+Please be aware that we will not accept pull requests which introduce new dependencies (to UI DLLs) to the WPF Designer. Reason: it is not possible to edit XAML screens which use these DLLs, when they for example have different versions.
+

README.md

@@ -3,7 +3,7 @@ The WPF Designer from SharpDevelop
 
 ##Overview
 
- WpfDesigner is a set of Assemblys wich can be included in your Project to implement a XAML GUI Editor.
+WpfDesigner is a set of assemblies which can be included in your project to implement a XAML GUI editor.
  
 ## Project Build Status
 
@@ -12,13 +12,13 @@ Branch | Status
 *master* (Development) | [![Build status](https://ci.appveyor.com/api/projects/status/iqxeo16r8ff9qv66/branch/master?svg=true)](https://ci.appveyor.com/project/icsharpcode/WpfDesigner/branch/master) 
 
 
-##System Requirements (running #Develop)
+##System Requirements (running SharpDevelop)
 
  - [.NET 4.5](http://www.microsoft.com/en-au/download/details.aspx?id=30653)
 
-##Libraries and Integrated tools:
+##Libraries and Integrated Tools
 
-For Sample App:
+Only the sample app has dependencies:
 * [Avalon Dock](http://avalondock.codeplex.com/)
 * [Avalon Edit](https://github.com/icsharpcode/AvalonEdit)
 
@@ -29,8 +29,4 @@ For Sample App:
 ##Sample App
 ![Sample App](/screenshot.png?raw=true "Sample App")
 
-##Infos for Pull Requests:
-
-Please be aware, that we will not accept Pull Requests wich introduce new Dependecys (to UI DLLs) to the WPF Designer, because with them is not possible to Edit XAML Screens wich use these DLLs, when they for Example have different Versions!
-
-######Copyright 2015 AlphaSierraPapa for the SharpDevelop team. SharpDevelop is distributed under the MIT license.
+######Copyright 2015-2016 AlphaSierraPapa for the SharpDevelop team. SharpDevelop is distributed under the MIT license.