[thor] Changes

[Carlos Pedrinaci]

Hi,

In order to confer a more flexible infrastructure to Thor I have applied
some of the ideas Jason raised on this list.
In particular Thor is now based on the Composite and Command patterns.

The system allows the creation of different kinds of projects with a set
of associated characteristics:
- Fixed attributes
- A set of Items that can be added and removed to every project.

The idea of using Items is that it would allow reusing them accross
different kinds of projects. Moreover these are just optional (unless
specified) parts a project.
Some typical examples of what could be an Item are:
- Deliverable
- Project Plan
- Bug Tracking system
- Forum
....

At the moment this is just starting to get into place but I think you
can get an idea of it..

Hope this clarifies that last commit :)

Regards,

Carlos