Fix logic for quoting special characters (#276)
Fix logic for quoting special characters (#276)

* Fix logic for quoting special characters

* Remove has_ucs4 from condition

on systems with `sys.maxunicode <= 0xffff` the comparison
(u'\U00010000' <= ch < u'\U0010ffff') can't be true anyway I think

yaml/pyyaml,anishathalye/pyyaml,yaml/pyyaml,anishathalye/pyyaml,yaml/pyyaml