support StaticVector

[tpapp]

Support StaticVector and possibly other StaticArrays.

Two possible use cases:

1. map an AbstractVector to StaticVector elements when that is required by the transformation. Pro: more flexible interface. Con: transformations would require a result type specification.

2. only map SVector to SVector, etc. This would keep the interface simple, but require conversion by the user, either for the inputs or the outputs. It is also conceivable that one would want to map an SVector to a bunch of MVectors.