Fix Reshape of HCATs

[nantonel]

Currently Reshape of HCATs and operators such as BlockArrays/ArrayPartitions is broken.
Possible solution by adding the following function:

function AbstractOperators.permute(T::Reshape{N,L}, p::AbstractVector{Int}) where {N,L}
    A = AbstractOperators.permute(T.A,p)
    return Reshape(A,T.dim_out) 
end
AbstractOperators.Jacobian(R::Reshape{N,L},x) where {N,L} = Reshape(Jacobian(R.A,x),R.dim_out)