Bug/move std to cvs

[wizofe]

Remove std, mean and complement and migrate to ColorVectorSpace.jl including tests.

closes #872
closes #698

[johnnychen94]

Thanks! Looks like exposure.jl needs to be removed as well (don't forget to remove the line include("exposure.jl") in Images.jl)

The test here fails because JuliaGraphics/ColorVectorSpace.jl#125 isn't merged yet. Retrigger the test after a new release in ColorVectorSpaces should give it a green check

[wizofe]

Thank you @johnnychen94 for your review. I did both changes and hopefully the tests will go through after merging as you predicted :)

Indeed I removed exposures.jl earlier but I forgot to push. Leaving this open now and moving my efforts to the other PR.

[johnnychen94]

Leaving this open now and moving my efforts to the other PR.

Sure, as you might already notice, the step 1 doesn't go very smoothly and more discussion is needed there. But for this PR I think it's ready.

Doing things parallelly is definite one most common thing in open-source would because most people don't do it as a full-time job and might not respond very quickly.

Looking forward to your next PR!

[kimikage]

JuliaGraphics/ColorVectorSpace.jl#125 was closed, and JuliaGraphics/ColorVectorSpace.jl#144 was merged.

Therefore, we need to limit the lower bound of [compat] (of ImageCore?) or add a hasmethod check to prevent redefinition of complement.

cc: @johnnychen94, @timholy