Big pull request with many improvement

Hi,
during the last four months we worked a lot on the marytts codebase, adding both general features and Italian-specific features.
As you can see from this pull request, we diverged a lot from the marytts codebase and it is now difficult to split the changes in a more clean way (moreover we have no time now to do so).

Some of the changes are still underdocumented and we think that they should be documented (maybe on wiki) before a release of this code. However I am scared that work on marytts/marytts can start again before these changes have been integrated.

Let me know what you think about this.

Bests,
Giulio.