R interface to (some of) cddlib
(<https://github.com/cddlib/cddlib>).
Converts back and forth between two representations of a convex polytope:
as solution of a set of linear equalities and inequalities and as
convex hull of set of points and rays.
Also does linear programming and redundant generator elimination
(for example, convex hull in n dimensions). All functions can use exact
infinite-precision rational arithmetic.