Fixed a (presumed) typo in documentation in matrix_view.rs.

Previously it says fixed_view and fixed_slice returns a matrix with `(R::dim(), CView::dim())` consecutive components. I just changed R to RView, because presumably this is a typo.

Fixed a (presumed) typo in documentation in matrix_view.rs.

Previously it says fixed_view and fixed_slice returns a matrix with `(RView, CView)` consecutive components. As per-input, and after re-reading the documentation and source code. Seems like RView and CView should be used instead of RView::dim() and CViem::dim().

Fixed spacing in documentation.

added mut_tr and the corresponding hidden yy_mul_to_uninit function.

added a test for mul_tr to verify that we get m.mul_tr(v) is m*v.transpose(). also changed the name of the previous test for tr_mul to clarify which side of the multiplication is being transposed.