Move github cat corner to const
Move github cat corner to const

PolymerLabs/playground-elements,PolymerLabs/playground-elements,PolymerLabs/code-sample-editor,PolymerLabs/code-sample-editor,PolymerLabs/code-sample-editor,PolymerLabs/playground-elements,PolymerLabs/code-sample-editor-package,google/playground-elements,google/playground-elements,PolymerLabs/code-sample-editor-package,google/playground-elements,PolymerLabs/code-sample-editor-package