math/f32, math/f64: new packages for vector and matrix types.

Change-Id: I937d16429d7321360d0b9f3a811f8d3d719e9bff
Reviewed-on: https://go-review.googlesource.com/6076
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Stephen Gutekanst <stephen.gutekanst@gmail.com>
2 files changed