Overlooks type differences of number and string in array

[Naoki Ando]

json-diff overlooks differences of number and string in array.

For example, when json-diff compares [1] with ["1"], returns nothing.

expected:

 [
-  1
+  "1"
 ]

[Eric A Woudenberg]

This is due to a but in Difflib. I have submitted a PR to fix this (but the last commit there was 2012): qiao/difflib.js#13