- All access to grid is now using the [] operator.
() always returns const, and is an evaluation over the domain.
- Now :
* () is always a call to evaluator (or a lazy expression).
* mesh_pt accepted by [] , both const and non const,
and not by ().
- Ported the libs (fourier et al.) but this break API.
- necessary otherwise the class gf and the namespace have
the same name, leading to some confusion, and need to qualify
some functions (specially on gcc).
Same naming conventions as arrays.
