mini optimization
make clear what "of course, the mycustom_theme needs to be registered too" means.
Update README.rst

s/stylesheets.xml/cssregistry.xml/ (there is no such thing as stylesheets.xml in Plone)
Merge branch 'master' of git://github.com/plone/plonetheme.sunburst
ported tests to plone.app.testing (doctest is still missing though)
make doctests pass again
document changes
Merge branch 'master' into plip-13705-remove-base
update changelog