Make print and show consistent for WindowsPaths

[rofinn]

Closes #87

@davidanthoff Would you mind reviewing this? I don't do a lot of work on Windows, so I'm not very confident that this won't break things.

NOTE: This seems to break compatibility with base Julia.

[codecov]

Codecov Report

Merging #88 into master will increase coverage by 0.78%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master      #88      +/-   ##
==========================================
+ Coverage   87.96%   88.75%   +0.78%     
==========================================
  Files          12       12              
  Lines        1039     1005      -34     
==========================================
- Hits          914      892      -22     
+ Misses        125      113      -12     

Impacted Files	Coverage Δ
src/windows.jl	52.94% <0.00%> (-30.40%)	⬇️
src/libc.jl	48.38% <0.00%> (-9.95%)	⬇️
src/path.jl	85.31% <0.00%> (+1.47%)	⬆️
src/test.jl	95.43% <0.00%> (+2.11%)	⬆️
src/posix.jl	89.47% <0.00%> (+4.47%)	⬆️
src/system.jl	91.73% <0.00%> (+5.68%)	⬆️

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[davidanthoff]

Hm, do we really want this? I mean, the standard way of representing windows paths is with backslash...

[rofinn]

I’m not sure, but it does seem weird that show already does this.

[davidanthoff]

So my gut feeling is that we would want to always use backslash for Windows path everywhere, given that that is the "normal" way on Windows. But I also don't know whether that might have negative consequences somewhere else ;)