Error when calling autorange with non-static transform

[Cody-G]

The error below occurs when tfm is not based on a StaticArray. It's a one-line fix, I'll do a PR shortly.

ImageTransformations.autorange(h, tfm)
ERROR: MethodError: Cannot `convert` an object of type Array{Float64,1} to an object of type Tuple
This may have arisen from a call to the constructor Tuple(...),
since type constructors fall back to convert methods.
Stacktrace:
 [1] autorange(::CartesianRange{CartesianIndex{2}}, ::CoordinateTransformations.AffineMap{Array{Float64,2},Array{Float64,1}}) at /home/cody/.julia/v0.6/ImageTransformations/src/autorange.jl:16
 [2] autorange(::OffsetArrays.OffsetArray{ColorTypes.Gray{FixedPointNumbers.Normed{UInt8,8}},2,Array{ColorTypes.Gray{FixedPointNumbers.Normed{UInt8,8}},2}}, ::CoordinateTransformations.AffineMap{Array{Float64,2},Array{Float64,1}}) at /home/cody/.julia/v0.6/ImageTransformations/src/autorange.jl:3

[timholy]

Fixed by #49