DOC: Remove dead gratipay links

README.md

@@ -1,6 +1,5 @@
 [![MATLAB FileExchange](https://img.shields.io/badge/MATLAB-FileExchange-orange.svg)][fex]
 [![Flattr this git repo](http://api.flattr.com/button/flattr-badge-large.png)][flattr]
-[![Gratipay](https://img.shields.io/gratipay/scottclowe.svg)][gratipay]
 [![Bountysource](https://img.shields.io/bountysource/team/matlab-schemer/activity.svg)][bountysource]
 
 
@@ -206,5 +205,4 @@ For details on how the method was implemented, see
   [matlab-schemes]: https://github.com/scottclowe/matlab-schemes
   [fex]:            http://mathworks.com/matlabcentral/fileexchange/53862-matlab-schemer
   [flattr]:         https://flattr.com/submit/auto?user_id=scottclowe&url=https://github.com/scottclowe/matlab-schemer&title=MATLAB-schemer&tags=github&category=software
-  [gratipay]:       https://gratipay.com/matlab-schemer/
   [bountysource]:   https://www.bountysource.com/teams/matlab-schemer