fixing the open command to use more portable webbrowser module

Author: eliasdorneles

Makefile

@@ -45,15 +45,15 @@ coverage:
 	coverage run --source skinfer setup.py test
 	coverage report -m
 	coverage html
-	open htmlcov/index.html
+	python -m webbrowser htmlcov/index.html
 
 docs:
 	rm -f docs/skinfer.rst
 	rm -f docs/modules.rst
 	sphinx-apidoc -o docs/ skinfer
 	$(MAKE) -C docs clean
 	$(MAKE) -C docs html
-	echo Open in your browser:  docs/_build/html/index.html
+	python -m webbrowser docs/_build/html/index.html
 
 release: clean
 	python setup.py sdist upload