Update version after 0.1.0 tag.
Update to Polymer 0.2.3.
Update shadow-dom combinators with their new names.

See http://drafts.csswg.org/css-scoping/#selectors for definitions.
Remove display:none elements when publishing.
Remove the version tag on master.

This makes it a bit easier to tag releases, since I don't need to also modify
master to match.
Warn if a function attribute element is a child of something other than <cxx-function>.

This ignores <ins> and <del> tags since I want to be able to mark that a whole
attribute is inserted or removed.

Fixes #6.