Fix Code injection in -d DELIM through use of eval (#150)

Replace eval with JSON.parse

This handles the code injection vuln in `-d DELIM`, but introduces a backward
incompatibility because JSON escapes are a subset of JavaScript escapes.

Co-authored-by: ready-research <72916209+ready-research@users.noreply.github.com>
Refs: #148

lib/json.js

@@ -126,7 +126,7 @@ if (util.format) {
 function _parseString(s) {
     /* JSSTYLED */
     var quoted = '"' + s.replace(/\\"/, '"').replace('"', '\\"') + '"';
-    return eval(quoted);
+    return JSON.parse(quoted);
 }
 
 // json_parse.js (<https://github.com/douglascrockford/JSON-js>)