Fix duplicate explicit target name

- Pypi requires strict reStructuredText syntax
- New make target `doc-check`

CHANGES

   - Support read output from ``svn diff --log`` and ``hg log -p``
   - Streamline reading large patch set
   - New ``--log (-l)`` option to read revision control diff log (thanks to
-    `Steven Myint <https://github.com/myint>`_)
+    `Steven Myint`_)
 
 Version 0.4 (2013-02-16)
 
 Version 0.0.3 (2013-02-04)
 
   - Publish on PyPI, supports read patch from file, pipe and diff output from
-    revision tools (thanks to `Steven Myint <https://github.com/myint>`_)
+    revision tools (thanks to `Steven Myint`_)
 
+.. _Steven Myint: https://github.com/myint

Makefile

 TESTPYPI = http://testpypi.python.org/pypi
 PYPI = http://pypi.python.org/pypi
 
-.PHONY: dogfood clean build dist-test dist \
+.PHONY: dogfood doc-check clean build dist-test dist \
 	test test3 cov cov3 html reg reg3 profile profile3
 
 dogfood:
 	./cdiff.py
 	git diff | ./cdiff.py -s
 
+doc-check:
+	./setup.py --long-description | rst2html.py --strict > output.html
+	python -m webbrowser -n "file://$(shell pwd)/output.html"
+	sleep 1
+	rm -f output.html
+
 test: cov reg
 
 test3: cov3 reg3