Adds basic support for images in game example

Initial version of working game with Box2D, images, nodes and sprites.

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/595e5ef3abf08ff479e3c5125bcb6468cc36fa4d

[viktorl, 2015-06-01 21:42:34]

viktorl@google.com changed reviewers:
+ eseidel@chromium.org

[eseidel, 2015-06-01 21:45:25]

Very cool.

[Cutch, 2015-06-01 21:55:16]

On 2015/06/01 21:45:25, eseidel wrote:
> Very cool.

Nice!

[abarth-chromium, 2015-06-01 21:58:55]

Neat!

https://codereview.chromium.org/1161023006/diff/1/sky/examples/game/lib/sprit...
File sky/examples/game/lib/sprite_node.dart (right):

https://codereview.chromium.org/1161023006/diff/1/sky/examples/game/lib/sprit...
sky/examples/game/lib/sprite_node.dart:10: SpriteNode() : super() {
The call to super() is implied.  You don't need to write it.

[abarth-chromium, 2015-06-01 21:59:08]

abarth@chromium.org changed reviewers:
+ abarth@chromium.org

[abarth-chromium, 2015-06-01 21:59:08]

LGTM

[eseidel, 2015-06-02 19:13:15]

You can land this with "git cl land" and it will automatically close this bug. 
If you've already landed some other way, then we can just close thsi.

[viktorl, 2015-06-02 22:09:07]

Committed patchset #1 (id:1) manually as
595e5ef3abf08ff479e3c5125bcb6468cc36fa4d (presubmit successful).