ready to make new release

Author: sg-s

+xolotl/version.m

@@ -1,2 +1,2 @@
 function version()
-disp('v20.9.8');
+disp('v20.9.15');

README.md

@@ -1,3 +1,5 @@
+[![View xolotl on File Exchange](https://www.mathworks.com/matlabcentral/images/matlab-file-exchange.svg)](https://www.mathworks.com/matlabcentral/fileexchange/79894-xolotl)
+
 # xolotl: a fast and flexible neuronal simulator
 
 [![Documentation Status](https://readthedocs.org/projects/xolotl/badge/?version=master)](https://xolotl.readthedocs.io/en/master/?badge=master)
@@ -74,6 +76,8 @@ Hooked? [Get started here](https://xolotl.readthedocs.io/en/master/).
 
 # Where do I get this?
 
+![](https://user-images.githubusercontent.com/6005346/93216395-ad3ced00-f735-11ea-8512-5915c4b70d87.gif)
+
 Click [here](https://github.com/sg-s/xolotl/releases/download/latest/xolotl.mltbx) to download, and click on the downloaded file to install.