[geometry] order of arrays

All,

the current spec says that arrays are in [1] column-major order, but it
seems that WebGL is in row-major order (ie [2]).
Can people confirm this? If so, maybe we should update the spec to match.

1: http://dev.w3.org/fxtf/geometry/#dom-dommatrixreadonly-tofloat32array
2: https://github.com/evanw/lightgl.js/blob/master/src/matrix.js