In the long term, a lot of this package should be removed in favor of the
golang.org/x/image/math/f32 package. The latter is the common location for
matrix types shared across graphics libraries. For example, the
golang.org/x/image/draw package refers to golang.org/x/image/math/f64.
Change-Id: I9d7ccd3cb35912e0d9dc5bd46c919516ea840340
Reviewed-on: https://go-review.googlesource.com/11856
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>