Inclusion check with VRep sets should use VRep algorithm

[schillic]

The following should work without Polyhedra:

julia> P = rand(VPolytope);
julia> P ⊆ P
ERROR: AssertionError: package 'Polyhedra' not loaded (it is required for executing `default_polyhedra_backend`)
Stacktrace:
 [1] macro expansion
   @ ~/.julia/dev/LazySets/src/Assertions/Assertions.jl:23 [inlined]
 [2] require(package::Symbol; fun_name::String, explanation::String)
   @ LazySets ~/.julia/dev/LazySets/src/init.jl:37
 [3] default_polyhedra_backend(P::VPolytope{Float64, Vector{Float64}})
   @ LazySets ~/.julia/dev/LazySets/src/Interfaces/AbstractPolyhedron_functions.jl:29
 [4] tohrep(P::VPolytope{Float64, Vector{Float64}})
   @ LazySets ~/.julia/dev/LazySets/src/Sets/VPolytope.jl:465
 [5] constraints_list(P::VPolytope{Float64, Vector{Float64}})
   @ LazySets ~/.julia/dev/LazySets/src/Sets/VPolytope.jl:386
 [6] _issubset_constraints_list(S::VPolytope{Float64, Vector{Float64}}, P::VPolytope{Float64, Vector{Float64}}, witness::Bool)
   @ LazySets ~/.julia/dev/LazySets/src/ConcreteOperations/issubset.jl:282
 [7] issubset(X::VPolytope{Float64, Vector{Float64}}, P::VPolytope{Float64, Vector{Float64}}, witness::Bool) (repeats 2 times)
   @ LazySets ~/.julia/dev/LazySets/src/ConcreteOperations/issubset.jl:297

This is the method that is currently used:

LazySets.jl/src/ConcreteOperations/issubset.jl

Lines 296 to 298 in 383ff0f

	for ST in [AbstractPolytope, AbstractHyperrectangle, LineSegment]
	@eval ⊆(X::($ST), P::AbstractPolyhedron, witness::Bool=false) = _issubset_constraints_list(X, P, witness)
	end

We should probably use this method:

LazySets.jl/src/ConcreteOperations/issubset.jl

Lines 207 to 218 in 383ff0f

	function ⊆(P::AbstractPolytope, S::LazySet, witness::Bool=false;
	algorithm=_default_issubset(P, S))
	@assert dim(P) == dim(S)
	if algorithm == "constraints"
	return _issubset_constraints_list(P, S, witness)
	elseif algorithm == "vertices"
	return _issubset_vertices_list(P, S, witness)
	else
	error("algorithm $algorithm unknown")
	end
	end

Note that this method should be adapted if both arguments prefer the VRep:

LazySets.jl/src/ConcreteOperations/issubset.jl

Lines 220 to 226 in 383ff0f

	@inline function _default_issubset(P, S)
	if applicable(constraints_list, S)
	return "constraints"
	else
	return "vertices"
	end
	end