XAFORUM-124 : Apply .xform when editing a topic

Another reason for which it is not a good idea to define wiki macros for development purposes is that (AFAIK) will be displayed in the WYSIWYG editor for all regular users that want to insert a macro in their currently edited page.

This macro does not make sense from a user's endpoint and thus, it should be defined and used as a velocity macro instead.

There is no point in propagating its miss-usage further.