tweight specialization on FixedPoint

[johnnychen94]

some tests in tst_rotation.jl are broken because the inferred weight type is incorrect. This might be due to recent upgrades in Interpolation and FixedPointNumbers.

julia> img = Gray{N0f8}[0.1 0.2 0.3; 0.4 0.5 0.6; 0.7 0.6 0.9];

julia> Augmentor.applyeager(Rotate(90), img); # eltype Gray{N0f8}

julia> Augmentor.applyeager(Rotate(90), N0f8.(img)); # eltype Float64 # not expected

A quick fix can be found in JuliaImages/ImageTransformations.jl#89 , but in the meantime, we need another patch in Augmentor to keep backward compatibility to old ImageTransformation versions.

[johnnychen94]

closed by #42