Item12819: Expand macros in Interwiki links

The macros are expanded after all token substitutions are made.

git-svn-id: http://svn.foswiki.org/trunk/InterwikiPlugin@17690 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
Item11587: Replace deprecated readTopicText

git-svn-id: http://svn.foswiki.org/trunk/InterwikiPlugin@17691 0b4bb1d4-4e5a-0410-9cc4-b2b747904278