Added functionality to PreCalculus to allow the ability to have equation numbering be used as link targets

XSL modified to pass ID into cnxml/html to allow link to be targeted utilizing link cnxml tagging.  There are three ways that this link works and produces selectors depending on markup: 1) equation, 2) informal, 3) inline.  All three possibilities accounted for in the modification of numbering.less.

Re-generated all CSS files due to numering.less change and regression tested all CCAP books.  Also 2 dbk2xhtml-core.xsl modified to be added to master for passing ID.  Moved code based onto naginata to generate PDF and test there as well.  Both tests look good.