stylesheets should support as broad range of XSLT implementations as possible
internationalized indexing code uses extension features that are not always available
internationalized index can not be part of default stylesheets
the actual code is designed as thin layer that will override definitions from default stylesheet
Shared code: common/autoidx-ng.xsl
FO specific code: fo/autoidx-ng.xsl
HTML output specific code: html/autoidx-ng.xsl