Modularize SanitizedFile#copy_to and SanitizedFile#move_to

[oss92]

I have edited some parts to decrease complexity and code duplication.

[thomasfedb]

Is this assignment required?

[thomasfedb]

I like the changes to SanitizedFile. The others I might need a little more convincing of.

[oss92]

As for the Mounter, The init_uploaders method saved a lot of code duplication.

As for MiniMagick, I guess assignment would be required. Maybe change reference_scale = scale_x >= scale_y ? scale_x : scale_y to scale_x = scale_y > scale_x ? scale_y : scale_x if you do not want an extra variable. But it would be less readable. What do you think?

[thomasfedb]

Perhaps something more like this:

scale_x, scale_y = width / cols.to_f, height / rows.to_f
scale = [scale_x, scale_y].max
cols, rows = [cols, rows].map {|dim| dim * scale }

[oss92]

I thought about this, but then you will have to deal with this scale == scale_x ? cmd.resize("#{cols}") : cmd.resize("x#{rows}").

Anyways I updated it.

[thomasfedb]

@oss92 Would you be able to split out the changes to SanitizedFile into a separate PR? I'd be very happy to merge those in without much trouble. The others might take a bit longer.

[oss92]

Done. Updated this pull request and will create another for the other changes if you'd like.