Function: matsize
Section: linear_algebra
C-Name: matsize
Prototype: G
Help: matsize(x): number of rows and columns of the vector/matrix x as a
 2-vector.
Doc: $x$ being a vector or matrix, returns a row vector
 with two components, the first being the number of rows (1 for a row vector),
 the second the number of columns (1 for a column vector).
