Row and column extractions on 2D tensors should use fixed views

[romeric]

We currently use dynamic views while extracting rows and columns of a 2D tensor

Tensor<double, 3, 4> A;
A(0, all)  --> TensorViewExpr<A>

this make it unnecessarily impossible to construct tensors of the right shape at compile time when we already know this info which is Tensor<double,4> in this case.

[romeric]

Related issue #157