Added DOI to latest stable release in README.md.

README.md

@@ -11,6 +11,9 @@ Try to join our Gitter chat: [![Join the chat at https://gitter.im/scattnlay/Lob
  
 Fill the issue here: [Issues](https://github.com/ovidiopr/scattnlay/issues).
 
+Latest stable release (v2.0.1)
+==============================
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.248729.svg)](https://doi.org/10.5281/zenodo.248729)
 
 How to use scattnlay
 ====================