saveDoc is having issues parsing certain JSON

Here's the stack of the error when I try to use `saveDoc`

Error: {"stack":"Error: invalid json: undefined Unexpected token ILLEGAL\n at IncomingMessage. (~/node_modules/felix-couchdb/lib/couchdb.js:185:29)\n at IncomingMessage.emit (events.js:81:20)\n at HTTPParser.onMessageComplete (http.js:133:23)\n at Client.onData [as ondata](http.js:1488:27)\n at Client._onReadable (net.js:677:27)\n at IOWatcher.onReadable [as callback](net.js:177:10)","message":"invalid json: undefined Unexpected token ILLEGAL"}