Fix path encoding problems on Windows

[azurefx]

See discussions on JuliaImages/Images.jl Issue 770

[azurefx]

Calling setimagefilename() will break TIFF images. Investigating.

[timholy]

Let's try rebuilding this.

[codecov]

Codecov Report

Merging #144 into master will increase coverage by 7.58%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #144      +/-   ##
==========================================
+ Coverage   53.26%   60.85%   +7.58%     
==========================================
  Files           2        2              
  Lines         306      304       -2     
==========================================
+ Hits          163      185      +22     
+ Misses        143      119      -24

Impacted Files	Coverage Δ
src/libmagickwand.jl	57.69% <100%> (+2.25%)	⬆️
src/ImageMagick.jl	65.57% <0%> (+15.57%)	⬆️

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[ViralBShah]

Merge? Or too old and close?

[ViralBShah]

3D TIFF: Error During Test at /home/runner/work/ImageMagick.jl/ImageMagick.jl/test/constructed_images.jl:142
  Got exception outside of a @test
  Sanity check on directory count failed, this is probably not a valid IFD offset. `TIFFFetchDirectory' @ error/tiff.c/TIFFErrors/567

[ViralBShah]

Would be nice to have this one working since it fixes a commonly reported issue (but this PR needs more work).