getRelativePath("foo", "foo")                       # "."
  getRelativePath("foo/bar", "foo")                   # "bar"
  getRelativePath("foo/bar", "foo/bar/yah")           # ".."
  getRelativePath("foo/bar/cool", "foo/bar/yah/sub/") # "../../cool"
  getRelativePath.default("/foo/bar/", "/bar/foo/")   # "../../foo/bar"
  # Windows
  getRelativePath("C:/foo/bar/", "C:/bar/")           # "../foo/bar"
  getRelativePath("C:/foo/bar/", "D:/bar/")           # "C:/foo/bar"Run the code above in your browser using DataLab