replace missing donation graphics with links

README.md

@@ -22,9 +22,10 @@ A framework for interactive code linting in the [Sublime Text 3](http://sublimet
 ## Share the love!
 Hundreds of hours have been spent writing and documenting SublimeLinter to make it the best it can be — easy to use, easy to configure, easy to update, easy to extend. If you use SublimeLinter and feel it is making your coding life better and easier, please consider making a donation to help fund development and support. Thank you!
 
-[![Donate Paypal](http://grotewold.me/assets/button-paypal.png)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=FK7SKD3X8N7BU)
-[![Donate Gratipay](http://grotewold.me/assets/button-gratipay.png)](https://gratipay.com/sublimelinter/)
-[![Donate Bitcoin](http://grotewold.me/assets/button-bitcoin.png)](https://www.coinbase.com/groteworld)
+Donate via: 
+* [**Paypal**](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=FK7SKD3X8N7BU)
+* [**Gratipay**](https://gratipay.com/sublimelinter/)
+* [**Bitcoin (Coinbase)**](https://www.coinbase.com/groteworld)
 
 ## Contributing linter plugins
 Please see the documentation on [creating linter plugins](https://sublimelinter.readthedocs.org/en/latest/creating_a_linter.html) for more information.