add rb and rtc to the list of 'generate implied end tag' elements
add FORK markers; handle autoclosing of rb and rtc
prevent parse errors on rb and rtc for end tags body and html
remove rb from list of obsolete, HTMLUnknownElement elements
ruby rendering
added new description of all ruby elements with examples and categorisation algorithm
ruby in appendices and usage summary
Merge pull request #17 from w3c/new-ruby

New ruby model