Updating the protocol generator for the ffgg family.

- Removed obsolete declarations, updating syntax conventions.
- Added a more useful origin comment.
Python attack renderer: do not abbreviate term leaves.

Abbreviating leaves is undesired and also contained a minor bug. This should now be fixed.
Python attack renderer backend: Cleaner unique naming.

By prefixing the temporary name with a space, we avoid any clashes with
user-chosen names.
Python attack renderer: Reintroducing explicit introduction of terms.