update SpriteKit project template: new icons, remove published resources, default to not export "phone" resources
SK plugin node: fix incorrect rotation
update SK submodule ref
publisher: extracted spritesheet generation into its own method
SK texture atlas generation script
Merge branch 'develop' of github.com:apportable/SpriteBuilder into develop-steffen
publish Sprite Kit texture atlas
update SK submodule ref
SK texture atlas: export one atlas to each individual resource-xxx folder
sktextureatlas export: texture atlas error detection and logging
Merge pull request #295 from KoboldKit/develop-steffen

SK: load image from atlas, various bugfixes, new icons