Patched svg files, and png from them, to allow subscript a to be rendered by RenderX for pdf.  (Note - always use Lucida Sans Unicode for maximum chance of symbols being rendered and/or displayed).

svn path=/trunk/libs/math/; revision=83405
Minor corrections from John 10 Mar 13

svn path=/trunk/libs/math/; revision=83406
Minor corrections from John 10 Mar 13

svn path=/trunk/libs/math/; revision=83407