Redefine transfroms as set of partially applied functions

- The deterministic transformations become partially applied functions
- The randomised transformations have their parameters bound twice,
once when the transformation is defined, second when the random
parameters are set before execution.
- We allow to overwrite any parameter passed to such applied function
during execution, so the `sz_y` can be expressed as argument `t(y,
sz=sz_y)`.

See