Add sphinx extension that replaces absolut RTD urls

This makes it possible to add proper links when showing an rst on github,
while also resolving it to relative links on readthedocs

README.rst

@@ -7,8 +7,8 @@ bootstrap-vz runs without any user intervention and
 generates ready-to-boot images for a number of virtualization
 platforms.
 Its aim is to provide a reproducable bootstrapping process using
-`manifests <http://andsens.github.io/bootstrap-vz/manifest.html>`__ as
-well as supporting a high degree of customizability through plugins.
+`manifests <http://bootstrap-vz.readthedocs.org/en/master/manifest.html>`__
+as well as supporting a high degree of customizability through plugins.
 
 bootstrap-vz was coded from scratch in python once the bash script
 architecture that was used in the

docs/conf.py

@@ -31,6 +31,7 @@ sys.path.insert(0, os.path.abspath(os.pardir))
 extensions = ['sphinx.ext.coverage',
               'sphinx.ext.autodoc',
               'sphinx.ext.linkcode',
+              'docs.replace_rtd_links',
               ]
 
 # Add any paths that contain templates here, relative to this directory.

docs/replace_rtd_links.py

@@ -0,0 +1,19 @@
+
+def setup(app):
+	app.connect('doctree-resolved', replace_rtd_links)
+
+	return {'version': '0.1'}
+
+
+def replace_rtd_links(app, doctree, fromdocname):
+	from docutils import nodes
+	import re
+
+	rtd_baseurl = 'http://bootstrap-vz.readthedocs.org/en/master/'
+	search = re.compile('^' + re.escape(rtd_baseurl) + '(.*)$')
+	for node in doctree.traverse(nodes.reference):
+		if 'refuri' not in node:
+			continue
+		if not node['refuri'].startswith(rtd_baseurl):
+			continue
+		node['refuri'] = re.sub(search, r'\1', node['refuri'])