Merge pull request #36 from jakirkham/fix_codeblock_docs

Fixes codeblock for `pip` installation

Author: LeeKamentsky

docs/index.rst

@@ -23,8 +23,9 @@ Installation and testing
 Install using pip
 -----------------
 
-    pip install python-bioformats
+::
 
+    pip install python-bioformats
 
 Running the unit tests
 ----------------------