Fix wrong canvas offset

- Copy inline style attributes from lowerCanvasEl to upperCanvasEl
- Copy classes from lowerCanvasEl to upperCanvasEl
- Add borderTopWidth, borderLeftWidth, paddingTopWidth and paddingLeftWidth (offsetAttributes) to canvas offset (fabric.util.getElementOffset) - these properties are not considered from getBoundingClientRect()
- JSfiddle's for tests
  - new: http://jsfiddle.net/Kienz/KRcsY/
  - old: http://jsfiddle.net/Kienz/xrMDr/

Fixes issue #347