into_nalgebra failed to work for 2d array with one row

[qqlearn123]

The following code section will panic:

let a = array!([[1.2, 2.3, 5.5]]);
let a2 = a.into_nalgebra();

[vadixidav]

@qqlearn123 I tried this with my latest changes in #17 and this seems to work, but you may have an issue with your array or may have indexed starting at 1 instead of 0. Notably, ndarray::array should be used like array![[1.2, 2.3, 5.5]], and not like array!([[1.2, 2.3, 5.5]]). If you use it with parentheses, it will create three axes (the parentheses are treated like square brackets, and it is confusing). Just in case I added a test in #17 (see here) that specifically tests the case of a one row array just to make sure it works.