Add basic copy/paste support in IText; fix certain char insertion.
Ensure one editing text at a time
Only fire dblclick if clicked at the same location
Lower node-canvas to 1.0.x
Add caching to IText which increases performance of large text tremendously
Build distribution
Slight reorganization
Fix itext styling due to caching
Fix `fabric.util.enlivenObjects` for empty `fabric.Group` objects
Add unit test
Fixes issue #943
Merge pull request #946 from Kienz/patch-2

Fix `fabric.util.enlivenObjects` for empty `fabric.Group` objects. Closes #943
[BACK_INCOMPAT] `fabric.StaticCanvas#backgroundImage` and `fabric.StaticCanvas#overlayImage` are `fabric.Image` instances. `fabric.StaticCanvas#backgroundImageOpacity`, `fabric.StaticCanvas#backgroundImageStretch`, `fabric.StaticCanvas#overlayImageLeft` and `fabric.StaticCanvas#overlayImageTop` were removed.
`backgroundImage` and `overlayImage` are now `fabric.Image` instances
New property `overlayColor` (analog to `backgroundColor`) - should be set with `canvas.setOverlayColor`
`backgroundImageOpacity` was removed => use `fabric.Image#opacity`
`overlayImageLeft ` was removed => use `fabric.Image#left`
`overlayImageTop ` was removed => use `fabric.Image#top`
`backgroundImageStretch` was removed => use `fabric.Image#width` and `fabric.Image#height`. If you scale your canvas you have to adjust the backgroundImage width/height manually.
Update SVG output.
Add 2nd parameter `firstLetterOnly` to `fabric.util.string.capitalize` => only first letter is transformed to uppercase (other letters stay untouched)
Add `preserveAspectRatio="none"` to `fabric.Image#toSVG` (otherwise streched backgroundImage and overlayImage didn't work as expected)
Update examples - TODO: Update jsfiddles for `setBackgroundImage` and `setOverlayImage`
Add unit test

Closes issue #270
Merge pull request #947 from Kienz/patch-1

[BACK_INCOMPAT] `fabric.StaticCanvas#backgroundImage` and `fabric.StaticCanvas#overlayImage` are `fabric.Image` instances. Closes #270
Added object controls visibility (github issue #552).