Add <span> tag and limited support for CSS styles to wxHTML.

Parse "style" attributes of the HTML tags and honour those of them that can be
mapped to the HTML 3 attributes.

Also add a handler for <span> tag.

Closes #10631.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64443 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/html/forcelnk.h

@@ -56,6 +56,7 @@ See mod_*.cpp and htmlwin.cpp for example :-)
     FORCE_LINK(m_hline) \
     FORCE_LINK(m_links) \
     FORCE_LINK(m_tables) \
+    FORCE_LINK(m_span) \
     FORCE_LINK(m_style)