AntTask buildfile inheritance for publications

Hi Lenya developers,

first I introduce the term "task buildfile" to describe
a buildfile that contains targets to be executed by the
AntTask.

I think it is useful to provide some basic targets in
a global task buildfile and to extend this in publications.

My idea is to allow a task buildfile for each publication
and merge it with the global task buildfile during the
build process using an XSLT stylesheet:

- targets with the same name are overridden
- targets with other names are added

What do you think?

Andreas