Don't depend on ImageTransformation

[johnnychen94]

ImageTransformations.jl is used to resize large images into smaller ones, but since displaying images in the terminal already losses lots of information, we could implement a much simpler subsampling method for this. The advantage is that we can make this package smaller by removing it (e.g., SpecialFunctions as one binary artifact is required by ImageTransformations)

package loading time with/without ImageTranformations:

• With: 5.043510 seconds (10.71 M allocations: 568.856 MiB, 2.16% gc time)
• Without: 3.133149 seconds (7.04 M allocations: 369.394 MiB, 4.49% gc time)

If JuliaImages/ImageCore.jl#106 got merged, it's likely to get another 1.5s reduction.

cc: @oxinabox

[johnnychen94]

closed by #54