scale_color_viridis() with scale_colour_viridis() alias

[ginolhac]

Thanks for a great package! Heatmaps with the viridis looks real nice and the fact to see the contrast in black & white mode is a plus. As a small enhancement, it would be nice to have the non American English spelling colour as an alias for the existing color functions. I am somehow used to @hadley's style and write scale_colour all the time. That doesn't break anything in ggplot2. Of low priority obviously.

[sjmgarnier]

@ginolhac This is certainly possible. I will try to include this in the next version of the package.

[sjmgarnier]

@ginolhac On CRAN now.

[ginolhac]

Thanks a lot @sjmgarnier ! Have a nice evening!

[sjmgarnier]

@ginolhac Thanks!