image: rename image.Tiled to image.Repeated.
What package image currently provides is a larger image consisting
of many copies of a smaller image.
More generally, a tiled image could be a quilt consisting of different
smaller images (like Google Maps), or a technique to view a portion of
enormous images without requiring the whole thing in memory.
This richer construct might not ever belong in the standard library (and
is definitely out of scope for Go 1), but I would like the option for
image.Tiled to be its name.
R=r, rsc
CC=golang-dev
https://golang.org/cl/
5530062