Photograb App Responsive Canvas

- The image is sized per maxWidth and/or maxHeight
- Which constrains the image by whichever is shortest
- Mediocre fix: maxHeight = retina iPad height
- Removed canvas borders in favour of a pickColor circle
Photograb UI

- Added a circular pick colour icon
- Added a rule to indicate 50 globes
- Set rule and canvas to 50% width
- Removed debugging information
Merge remote-tracking branch 'upstream/master'