Polytopes' intersect should be intersection

[mforets]

Concrete intersection has been called "intersection", while lazy intersection is ∩ , spelled out as "intersect", for the case of rectangles:

julia> B1 = BallInf(ones(2), 1.);

julia> B2 = BallInf(ones(2), 1.);

julia> intersection(B1, B2)

LazySets.Hyperrectangle{Float64}([1.0, 1.0], [1.0, 1.0])

julia> intersect(B1, B2)
LazySets.Intersection{Float64,LazySets.BallInf{Float64},LazySets.BallInf{Float64}}(LazySets.BallInf{Float64}([1.0, 1.0], 1.0), LazySets.BallInf{Float64}([1.0, 1.0], 1.0))

This is to propose adjusting the function's name in

    intersect(P1::HPolytope{N}, P2::HPolytope{N};
              [backend]=CDDLib.CDDLibrary(),
              [prunefunc]=removehredundancy!)::HPolytope{N} where {N<:Real}

and the corresponging one for VPolytope.