Merged readme.

Author: PhilJay

README.md

@@ -41,6 +41,7 @@ Questions & Issues
 If you are having questions or problems, feel free to contact me. Since I would very much like that other users of this library **can also benefit** from your question, I am asking you to contact me via e-mail **only as a last option**. Instead, you should:
 
  - Make sure you are using the latest version of the library. Check the [**release-section**](https://github.com/PhilJay/MPAndroidChart/releases).
+ - Study the [**Documentation-Wiki**](https://github.com/PhilJay/MPAndroidChart/wiki)
  - Search or open questions on [**stackoverflow**](https://stackoverflow.com/search?q=mpandroidchart) with the `mpandroidchart` tag
  - Search [**known issues**](https://github.com/PhilJay/MPAndroidChart/issues) for your problem (open and closed)
  - Create new issues (please **search known issues before**, do not create duplicate issues)