Update README.md

Author: jcesardasilva

README.md

@@ -1,6 +1,7 @@
 # optscan
 Optmization of scan grid for scanning microscopy using a solver for the travelling salesman program implemented in Google OR-Tools 
 <https://developers.google.com/optimization/routing/tsp>
+
 The implementation here is published here [[1]](https://doi.org/10.1107/S1600577519006301). We will be happy with your citation if you use it. 
 
 Installation