Merge pull request #7 from oreillymedia/sarah

removing autogenerated header content in document template
Merge pull request #8 from oreillymedia/sarah

fixing autogenerated headers in document templates
Merge pull request #10 from oreillymedia/sarah

Removing autogenerated figure label
moved figcaption tag below img tag in block image template
Merge branch 'master' of github.com:oreillymedia/asciidoctor-htmlbook into sarah