Image layers now load completely before successive layers are drawn, in addition to other improvements

- Shapes masked by another shape will no longer be clickable outside of
the masked region (this is the correct behavior)
- The drawLayers() method now automatically restores any masks that
haven't already been restored
- Fixed a bug in which the setPixels() method would manipulate the
entire canvas even if the a custom width or height was set
Fixed a bug which affected image layer transformations
Draggable grouping has landed in jCanvas, as well as many new methods and fixes.

NEW
- Draggable groups have been implemented in this latest release. Simply
set a layer's 'dragGroupWithLayer' property to true. As a result,
dragging that layer will move all layers in the same layer group. For
examples, see the documentation.
- Added a new setLayers() method for easily setting properties of all
layers (rather than a specific layer)
- The setLayer() method can now be used to assign events at any point
after a layer's creation. Before, adding events could only be done when
initially creating a layer
- Added a new getLayerIndex() method for accurately retrieving a
layer's index
- Added the animated layer as a third argument to the callback function
for the animateLayer() method
- The getLayers() method now accepts an optional function argument
which will be used as a callback to filter the layers array
- The animateLayer() method now allows you to use functions as values
for any of the properties to be animated

CHANGED
- The drawGraph() method has been deprecated

FIXED
- Fixed a bug which prevented layer events from firing if an image
layer was present
- Fixed a bug in which clearing part of the canvas using clearCanvas()
did not respect transformation properties (rotate, scale, etc.)
Fixed a bug regarding the 'type' property
Fixed a bug which raised an error when calling removeLayerGroup()
Fixed a bug which affected text wrapping (#83)
Fixed a bug which prevented the drawing of layers if an image layer's 'visible' property was false
Fixed a bug which may affect the drawing of image layers
Fixed issues #87, #86, and #85
Added a new dragcancel event for when the user mouses off the canvas while dragging

- The jCanvas parameters object is now the second argument to the
draw() method's fn callback
- Fixed issues #91 and #89
- Fixed an issue in which drawing a single image layer with drawLayer()
would unintentionally draw all layers
Added a new respectAlign property for text

See the documentation for details:
http://calebevans.me/projects/jcanvas/docs/text/
Fixed a bug in which the removeLayers() method caused an error
Fixed a bug which prevented drawLayers() from being called within an event callback
The stroke of a shape now responds to events

- This change fixes issue #96.
- Also added a new shadowStroke property to satisfy issue #94
Modified the fix for issue #96
Fixed an encoding error in the readme and license files
Fixed a potential issue with jCanvas event bubbling (#97)
Reverted the change made in the previous commit
Fixed issue #101, which affected image layers and masks
Added a new detectPixelRatio() method for detecting devices with high-resolution displays (#102)

See the documentation for details:
http://calebevans.me/projects/jcanvas/docs/detectPixelRatio/