v0.9.0

culori.interpolate() now supports:

• color stop positions
• interpolation hints (midpoint positions)
• easing functions

Color stop positioning and interpolation hints are based on the CSS Images Level 4 working draft, but differs slightly in that interpolation hints don't alter the position of color stops.

Support for easing functions* inspired by @meyerweb's proposal.

*Easing functions not included.