CUDF solver integration for APT

 apt-cudf provides integration among the APT package manager and CUDF solvers,
 allowing APT to rely on external (CUDF-based) dependency solvers to plan
 package installation, upgrade, and removal.
 .
 CUDF is a distribution-independent, standard format to describe dependency
 solving scenarios, as faced by package managers in popular package-based
 GNU/Linux distributions. APT is a well-known package manager for Debian-based
 distributions, which is able to delegate dependency solving to external
 solvers, by the means of the External Dependency Solving Protocol (EDSP).
 .
 apt-cudf provides the glue between the EDSP protocol and CUDF solvers,
 enabling any installed CUDF solver to be used as an external solver for APT.
 .
 Several CUDF solvers are available in Debian. They all provide the cudf-solver
 virtual package.