Merge pull request #100 from oreillymedia/pdf-bookmarks

Handling for PDF bookmarks and xspec tests
Refactoring for heading processing for PDF bookmarks.
Fixed bug in selection of child nodes for headings in title.markup mode (used //node() instead of /node()
Merge pull request #101 from oreillymedia/tocgen

Fixed bug in selection of child nodes for headings in "title.markup" mode
Merge branch 'master' of github.com:oreillymedia/HTMLBook into pdf-bookmarks
Moving "process-headings" template to common.xsl