[Grace-core] Class syntax and type parameters

[Marco Servetto]

It is now a long time that grace is fighting to balance
Generics -- Incremental typing -- Traits --- Classes as derived concepts.

Why we want genercis a la java instead of generational code a la c++
templates (but safer)

Why we can not have
class PointList =Collections.list(Point) ??

are we sure that for a Didactic language, having parametric
polimorphism is a good idea?
Why are we so sure?