Merge SyntagmaticFunction and subclasses.

[vletard]

Given the current type hierarchy, it seems that there is no real use of having Process, Actant and Quality to subclass SyntagmaticFunction apart from some degree of code clarity.
Indeed the three subclasses represent the same underlying object as a plain SyntagmaticFunction. Moreover there is a risk of unwanted parent class delegation (particularly for static similarly named methods).
The simplest option is to make subclasses methods to have distinct names from SyntagmaticFunction's.
A better choice is to completely merge all four classes into a single big one.