* src/print-xml.c (print_core): Remove item set

* src/print-xml.c (print_core): Remove item set
redundancy.
* data/xslt/bison.xsl (bison:ruleNumber): New key.
Improve processing time. Suggested by Joel E. Denny.
* data/xslt/xml2dot.xsl (xsl:template name="escape"):
Write xsl:param "required" attribute as comment.
* data/xslt/xml2text.xsl (xsl:template match="item"): New.
(xsl:template match="rule"): Support new reduced itemset.
(xsl:template match="point"): Remove.
* data/xslt/xml2xhtml.xsl: Likewise.