shiny/example/goban: example program: Go board

This is an example, still rudimentary, of shiny graphics in action.
This commit has the basic geometry, images, and rendering, but
is missing all the game logic, resizing the board on demand, and
so on, but one can actually play a game using it if one wants.
It has all the built-in computing power of a physical Go board.

Drawings by Renee French. The grid will become a hand drawing
too, soon.

A simple checkpoint.

Change-Id: Id235fa677c59d18cfee0dd96380a0cbca2232c29
Reviewed-on: https://go-review.googlesource.com/14002
Reviewed-by: Nigel Tao <nigeltao@golang.org>
30 files changed