Make the differences a bit clear

[pedro-teixeira]

In the canvas diff would be great to have the background a little bit white transparency and the differences in red.

This should be in a config file that you can choose if you want background, whats the transparency and whats the color of diff.

[stefanjudis]

I know a guy that could solve that. :P

[stefanjudis]

@chaeringer could you please check Readme if it's acceptable now? :)

I think, after that we can push new version.

[stefanjudis]

Shipping with 0.8.0.