PlaygroundBook 更新

cocoapods installテスト実施

Swift バージョン情報を更新

Update book

podspec の swift_version 指定方法変更

v0.15.0

TortoisePlayground.playgroundbook.zip 0.14.0

podspec 更新

Merge pull request #32 from temoki/develop

Fix bug: penSize state are shared in tortoises.

Merge pull request #31 from temoki/develop

Add shape feature