add preamble for survey-likert
add preamble for survey-likert

related to issue #94

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