alexcb/rjson — pull request #4 by earlye (2014-10-31 15:41:31+00:00)
Title: Fix low-value control characters when escaping strings from R to JSON

It turns out that characters other than \r\n\t, but with ordinal values <= 0x1F or equal to 0x7F, are also control characters that JSON requires be escaped using \uHHHH format.