Adding xref-pagenum-style template for generating data-xref-pagenum-style attr values.
@data-xref-pagenum-style handling for XREFs.
Handling for data-xref-pagenum-style attributes for index entry generation.
Toggle data-xref-pagenum-style attr with autogenerate.xref.pagenum param for XREFs.
Renaming param for clarity.
Handling in chunk.xsl for data-xref-pagenum-style attrs.
Updated comment.
Merge pull request #163 from oreillymedia/xref-pagenum-style

Adding support for "pagenum" style functionality