bug fix core - adding root document element addition by default
bug fix core - adding root document element addition by default

jspsych/jsPsych,wolfgangwalther/jsPsych,erikasf/jsPsych,andyh616/jsPsych,andyh616/jsPsych,jodeleeuw/jsPsych,Scienthusiast/jsPsych,wolfgangwalther/jsPsych,vergenzt/jsPsych,shamrt/jsPsych,vergenzt/jsPsych,jspsych/jsPsych,Scienthusiast/jsPsych,adrianoesch/jsPsych,jspsych/jsPsych,msrresearch/jsPsych,shamrt/jsPsych,erikasf/jsPsych,adrianoesch/jsPsych,jspsych/jsPsych