Link to working docs
Merge pull request #609 from maxsnew/fix-docs-link

Link to working docs
Removed ImageSize constraint

Closes https://github.com/PistonDevelopers/graphics/issues/610
Merge pull request #611 from bvssvni/master

Removed ImageSize constraint
Fixed number of colors

Closes https://github.com/PistonDevelopers/graphics/issues/612
Merge pull request #613 from bvssvni/master

Fixed number of colors
Update name in README/Travis link