interface: the compiler does not/cannot check whether the class
    implements all required methods in that case, and it moreover leads to
    crashes (mantis #24184). Older versions of Delphi did allow this (and
    don't check whether the interface methods are implemented either), but
    that's simply a (similar) bug in Delphi that has been fixed in XE at
    least
  * fixed compilation of webtbs/tw2727 after this fix

git-svn-id: trunk@24177 -