DBFW

The Template subsystem is currently quite a mess. It doesn't make any distinction among the interfaces provided by all objects that participate to the template instantiation, it doesn't support template nesting and it presents way too many code duplication.
The refactoring goals are:

• remove all duplications of code
• clearly separate the code used to render a template from the template structure (think of something MVC-like)
• clearly define the interfaces that must be provided by various classes to support the template instantiation
• add support for in-flow instantiation (through the two-phases instantation, activated when the instantiation process finds an object among the participants that requires a separate generation step)
• support recursive template nesting, where it makes sense

All the development will be done in a separate branch created ad-hoc.