Update dev docs with testing and doc generation

DEVELOPER.md

@@ -16,5 +16,15 @@ Extract the tarball in the tests directory and run tox from the root directory.
 
 Please make sure your code passes all tests before opening pull requests.
 
-All the best,
-William Tisäter
+### Testing
+
+You can run all tests if you from root type `tox`. This requires a machine
+with Python 2.5 - 3.3 installed and all dependencies mention in the header.
+
+### Documentation
+
+The documentation can be re-generated by running following command from root:
+
+    epydoc --config=epydoc.ini --no-private
+
+-- William Tisäter