fix #35 ; simplify code a bit

[timotheecour]

• fix [critical] walkGlob doesn't work with un-normalized paths (eg containing //); os.walkFiles works #35
  /cc @citycide

I've simplified code a bit by adding this:

 when pattern is string:
    let pattern = pattern.glob

so that the remaining code only has to deal with Glob, not string; my understanding is this should have no performance impact in the sense I doubt the code would be more efficient when using a simple string pattern as opposed to a Glob object (eg because file operations should be more expensive anyways); but let me know if you disagree

[haltcase]

I like the simplification, and I agree - I doubt there's a significant change in performance. We'd have to benchmark anyway.

Thanks!