Added support for new boostbook <access> element for documenting non-public
class members.
function.xsl, type.xsl, utility.xsl: Added support for <access> elements to
allow nonpublic access specifiers for class member documentation.
boostbook.dtd: Updated to reflect new <access> element. Updated Peter Simons
email address. Added mention of boost license.
reference.dtdxml: Added reference documentation for new <access> element.
Removed some obsolete remarks from the description of inherit element.
reference.xml: The changes to this file were generated by applying
dtd2boostbook.xsl to the updated reference.dtdxml file.