Casting `Vector{Complex{T}}` to `Vector{T}` of twice the size

[fredrikekre]

julia> x = rand(Complex{Float64}, 2)
2-element Array{Complex{Float64},1}:
 0.8199153266362134 + 0.6218323711392901im
 0.9962922034287771 + 0.8647751860682487im

julia> reinterpret(Float64, x)
4-element reinterpret(Float64, ::Array{Complex{Float64},1}):
 0.8199153266362134
 0.6218323711392901
 0.9962922034287771
 0.8647751860682487