fix #36; correctness wrt symlinks

[timotheecour]

• fix [critical] walkGlob doesn't work with symlinks in pattern; unlike ls, os.walkDir etc #36
  /cc @citycide

[haltcase]

@timotheecour thanks for the fix. Looks like this affects the ability to find paths case-insensitively on macOS (and likely Windows¹), can you review that?

https://travis-ci.com/citycide/glob/jobs/277020797#L208

¹ seems AppVeyor has made VS projects the default mode within the last year, which broke the Windows tests. I should look into putting everything into GitHub actions at some point.

[timotheecour]

@citycide PTAL
it's not 100% ideal but should be correct for all purposes and definitely better than behavior prior to this PR; ideally we'd have a way to resolve case (but not resolve symlinks) but no idea how to do that; it should be correct though; eg:

on OSX:
mkdir TEMP
ls temp # works

I've asked on stackverflow here https://stackoverflow.com/questions/59797065/how-to-get-original-case-of-a-path-on-osx-eg-tmp-tmp how we can resolve a path to its original case (eg: mkdir TEMP; getOrigCase(temp) => TEMP) ; we can improve later if there's a way

¹ seems AppVeyor has made VS projects the default mode within the last year, which broke the Windows tests. I should look into putting everything into GitHub actions at some point.

how about switching to azure pipelines, like Nim did? (so you only need 1 pipeline instead of 2, as it's cross platform)

[haltcase]

@timotheecour hmm.. I suppose it's alright not to maintain the casing if it's not reasonable to do it without also resolving symlinks. I'm not even really sure how important it is tbh, I just always considered it sensible. Maybe we wait a bit and see if the universe gives us an answer via your SO question.

As for the CI provider, travis & github actions both also support macOS, windows & linux at this point. I don't know much about azure pipelines yet, but the easiest option (to combine providers) would be to just enable windows in travis.

[timotheecour]

ping now that travis supports (osx, windows, linux); resolving symlinks as was the case before this PR was bad (eg caused #36)
not maintaining the case on OSX is ok since OSX is case insensitive anyway:
mkdir FOO && cd foo works; it's just that the original case is not maintained ; if the stackoverflow question gets an answer we can always improve this here