Refactoring chunk logic to split "chunk-for-node" into a separate function that can be called from other templates.
Refactoring to make $chunks variable global to the chunk.xsl stylesheet.
First pass at handling for "previous" link generation.
First pass at handling for "next" and "toc" navigation links.
Merge branch 'master' of github.com:oreillymedia/HTMLBook into htmlbook-xsl
Merge pull request #89 from oreillymedia/htmlbook-xsl

Support for PIs for navigating among HTML chunks