Enable register command as make target

The register command registers the package on PyPI as a public package.
diff --git a/Makefile b/Makefile
index 6b54824..ad6d0be 100644
--- a/Makefile
+++ b/Makefile
@@ -8,8 +8,8 @@
 sdist:
 	python setup.py sdist
 
-# register:
-# 	python setup.py register
+register:
+	python setup.py register
 
 site:
 	cd docs; make html