Undefined variables in POIExt

[danareu]

• The variable 𝒽 in ext/POIExt/model.jl is undefined (line 48). It should be 𝒽₀.
• The variable op_per_strat in ext/POIExt/model.jl is undefinded (line 48).

    if use_op_per_strat
        𝒯ᵣₕ = TwoLevel(1, 1, SimpleTimes(durations(𝒽)); op_per_strat)
    else
        𝒯ᵣₕ = TwoLevel(1, sum(durations(𝒽₀)), SimpleTimes(durations(𝒽₀)))
    end

[JulStraus]

Closed by #11