Cache actual bounding box of the Pen arrow shape

for improved collision detection
Improve edge-collision detection of default sprite “arrow” shape
Really fix setting the cloud as default save location when logged in
Experimental “ForEach” primitive (hidden in dev mode)
Merge pull request #665 from cycomachead/cloud-default

Really fix setting the cloud as default save location when logged in
fix typo & update history
Avoid auto-scaling artefacts in Safari on retina displays

(resulting in “traces” when dragging items)