1. Add links from topic in <relrow> to topic in <relheader> and vice versa.
We should update the maplinkImpl.xsl to support this requirement, add the new links to maplinks.unordered in the right format. We can assign the new generated links to the role of friend, but we may also don't. If we don't, we should think about a new role to name it.
Element <relcell> and <relcolspec> may contain more than one topics, and the topics can be nested and paralleled, the spec of this requirement is not clarity about this situation, we are not clear about this.
2. Read and move links.
MapLinksReader reads the links recorded in maplinks.unordered, and use DitaLinksWriter to insert the link information into related dita topics. MapLinksModule may not be affected by this requirement, because they just only move the links and the link information are arealdy generated by maplinkImpl.xsl.
3. Change groupe title.
We need to replace the groupe title with @navtitle or navtitle specified in <relcolspec>.
If @navtitle or element <navtitle> is not specified in <topicref> under <relcolspec>, use the normal DITA 1.1 processing. When @navtitle or element navtitle is given, we should grab it from the right location in the map to serve as the groupe title. Groupe title is created in xsl/xhtml/rel-links.xsl or xsl/common/related-links.xsl, so we need to update them to support this function.