Patches `padarray` so that it works on `OffsetArray`

[zygmuntszpak]

Using the padarray function with the Fill type on an OffsetArray resulted in an error. This was caused due to an implicit call of size on an OffsetArray which is an undefined operation. This commit patches the bug JuliaImages/Images.jl/issues/718

[codecov[bot]]

Codecov Report

Merging #61 into master will increase coverage by <.01%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #61      +/-   ##
==========================================
+ Coverage    91.5%   91.51%   +<.01%     
==========================================
  Files           8        8              
  Lines        1095     1096       +1     
==========================================
+ Hits         1002     1003       +1     
  Misses         93       93

Impacted Files	Coverage Δ
src/border.jl	96.89% <100%> (+0.01%)	:arrow_up:

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[zygmuntszpak]

I've changed it to your suggestion, but I'm wondering why we ought to use Compat.axes and not OffsetArrays.axes in this instance?

[Evizero]

Because as far as I can tell that's where the axes actually comes from. OffsetArrays.axes works because that package also uses that function. As I understand axes is the 0.7 version of indices, so for backward compatibility Compat provides some glue code to also make it work in 0.6. It seems in 0.6 its just a reference to indices

at least thats my impression when looking at https://github.com/JuliaArrays/OffsetArrays.jl/commit/ce854a71a9e96eba081d48144b9df66928ebdc91