Allow for object-style parameters, "json" and "path"

lib/jsonpath.js

@@ -45,7 +45,7 @@ function JSONPath (opts, obj, expr) {
     this.sandbox = opts.sandbox || {};
 
     if (opts.autostart !== false) {
-        return this.evaluate(obj, expr);
+        return this.evaluate(obj || opts.json, expr || opts.path);
     }
 }