UX : Include UX fix on piskel app for swap colors

- Also updated robots.txt to disallow template folder
- minimap zoom border is now rgba(255,255,255,0.5)
Bug : Cannot clone your own piskel if private

Updated conditions for cloning a piskel
- if piskel private, authorize if owner
- if piskel is public, authorize if logged in
Update piskelapp-editor version
Various updates :

- integrate new piskelapp-editor version in editor.html (new template
  defined)
- start animating sprite when on /view
- updated piskel-animated-preview to support new mode : always animate
- added opengraph and twitter card support on /view and /edit