Update index.rst

Remove use of google cloud gadget to resize logo image. Not quite sure of the implications of this are.

Author: IanSudbery

doc/index.rst

@@ -3,7 +3,7 @@
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.
 
-.. image:: https://images1-focus-opensocial.googleusercontent.com/gadgets/proxy?url=https://cloud.githubusercontent.com/assets/6096414/19521726/a4dea98e-960c-11e6-806a-a18ff04a391e.png&container=focus&resize_w=550
+.. image:: https://cloud.githubusercontent.com/assets/6096414/19521726/a4dea98e-960c-11e6-806a-a18ff04a391e.png
 
 Tools for dealing with Unique Molecular Identifiers
 ====================================================