Avoid endless recursion in ToolEvent#middlePoint.

Closes #257.
Include Acorn / Esprima only into local PaperScript scope, and locally deactivate AMD.

Closes #255.
Add simple BooleanOperations Node example, illustrating how to serve results through a HTTP server.
Define PaperScope#activate()

Closes #256.
Fix blurriness in Item#rasterize().

Closes #258.
Allow combinations of blendMode and opacity.

Closes #259.
Add support for canvas compositing modes to Item#blendMode.

Closes #159.
Avoid use of 'window' for Node, and pass on reference to root scope instead.
Use fire('frame') instead of onFrame(), to correctly handle frame events on Node.
Fix faulty comment about _handleFrameItems.
Separate requesting and handling of animation frames.

Closes #176.
Add support for shadows.

Closes #36.
Only test for fill in Item#_hitTest() if options.fill is set.
Define failing test about Item cloning hierarchy.

Cloned items should be inserted right above their originals.
Implement insert parameter in Item#clone() to control DOM insertion.

Defaults to true. Also insert in the right place now, above the original.
Fix active layer test when calling Layer#clone().
Use insert: false option in creation of all clones.

Still needs implementing in Item constructor.
Filter out the insert parameter in _set for now, to prevent issues with cloning().

Work in progress.
Do not insert boolean operation clones into DOM.
Allow Base#_set() to exclude properties.