Move replace solution types from the bindings to the library

Move replace solution types from the bindings to the library

This adds two new functions:

solver_all_solutionelements()
return a queue with (type,p,rp) solution triplets.

solver_solutionelementtype2str()
this is similar to solver_solutionelement2str(), but also takes a
type parameter so that the replace types result in different strings.

Make use of the two functions in the example solver to
show how they work.