Fixed hessian(SXMatrix) implementation exposed due to 74d4a09c9dc66020ad7ab1df6dca2d883d5265ec
Added inner product MX node
Added derivative propagation rules for InnerProd
Added evaluation for InnerProd
Added sparsity pattern propagation and codegen to InnerProd
Enabled new InnerProd class for MX
Enabled inner_prod for scalar-matrix binary operations adjoint propagation
Shallow water: removed flattening step in exact Hessian objective
Implemented Frobenius norm
Added derivative rule to Inverse
Added derivative rule to Determinant