Release 1.19.0
Update grunt-spritesmith.js

Added full filepath to image data.
Update README.md

Documented add full filepath to image data.
Changed image.file > image.source_image
Changed file > source_image
Added description for source_image
Fixed up broken expected files
Relocated `source_image` to other images
Release 1.20.0
Upgraded to latest spritesmith for pngsmith engine