Merge recipes for polygons and add polytopes

[mforets]

Closes #574.

[schillic]

Why not just use AbstractPolytope? vertices_list should exist for all types.
If we have more efficient implementations, they will be chosen automatically.
See #574.

[schillic]

You also need to adapt the unit tests in unit_plot.jl.

[mforets]

Yeah you're right, i agree to plot every AbstractPolytope exactly by default. I think it's more natural than plotting a box overapproximation. If the user wants to plot an overapproximation of the set, plot_lazyset(S::LazySet, ε::Float64) can still be used.

[mforets]

See #574.

Do you agree this closes #574?

[mforets]

You also need to adapt the unit tests in unit_plot.jl.

I had a look, but what is there to change? I wouldn't delete tests even if they are now called from the same recipe. (since for each different type they are testing different code paths)

[schillic]

without Union (same below)

[schillic]

Do you agree this closes #574?

Yes.

You also need to adapt the unit tests in unit_plot.jl.

I had a look, but what is there to change? I wouldn't delete tests even if they are now called from the same recipe. (since for each different type they are testing different code paths)

You may need to replace the @test_throws X plot(y) with just plot(y). Just run the tests locally and see if they pass. I am not sure.