Issue #50 : set default selected index to -1 so that we are not setting default answers for user and also get UI rendering properly at the same time
Issue #51 : change Done button title to Save, so that user knows if he/she goes back, that means cancel.
Issue #60 : add validation to user input, add an alert after user input is submitted, fix userEmail bug, change Save button to Submit
Issue #51 : code refactoring: move the creation of survey submission event to PacoEvent
Issue #51 : add experimentVersion to survey submission event
Issue #77 : fix the survey event payload for likert, likert_smiley, and list
Issue #77 : improve code efficiency
Issue #81: fix a bug so that submitting a survey only submits visible questions' answers
Issue #81 : remove unuseful log
Issue #51 : fix the validation bug for List
Merge pull request #79 from google/issue51

Issue #51