Fix typos in comments.
Merge pull request #265 from duckmaestro/master

Fix to #263: _children undefined inside call to myShape.isEmpty().
Merge pull request #262 from huochunpeng/fix_typo_in_matrix

fix typo "Concatentates".
Do not apply operator overloading in situations where UpdateExpressions happen inside other contexts that would cause a change of behavior, e.g. array[i++], or if (i++ < 1).
Closes #260.
Take Item#matrix into account when drawing gradients.

Closes #267.
Implement Raster#getSubRaster() and document both #getSubImage() and #getSubRaster().
Rename Raster#getSubImage() to #getSubCanvas(), and use insert: false combined with #insertAbove() to correctly insert newly created rasters.
Merge Raster#setImage() and #setCanvas().
Use named module AMD syntax for defining paper.

Closes #261.
Correctly detect image size on all browsers.

Closes #268.
Add mouse hovering to StrokeBounds example.
No need to pass false for allowNull as it's the default.
Remove caching of inverse transform.

View#matrix can be directly modified, and we don't have change tracking on matrices yet.
Fix documentation irregularities.
Fix issue with importing SVG document nodes.

Closes #276.
Boolean -fix: CurveLocation now keeps track of the correct segment at intersections
Docs: Fix shadow example.
Boolean -fix: Preserve the order of intersections found (Curve-Line) according to the PathItem they belong to.
Boolean -fix: Correctly perform boolean operations regardless of the input paths' winding direction
Conform to paperjs coding style.