modified alpha and createSession
Added email and date validation
FIXME: QueryHelper
Minor refactoring...
Fixed minor bug in QueryHelper
Removed debug statement
Added unit test
Created beta page and refactor js code for video
Added user list to beta version
refactor the createSession.js

improve the UI
Change InputValidator and refactor QueryHelper

- Change inputValidator :
* format to Y-m-d
* today is valid date
-Change in QueryHelper
* add_user now return nothing, and throw exception if email is not valid
Updated MailSender
Maps url relative to the current environment.
Added email template
Told JSON constructor to send email to users for each session generated
Updated unit tests
Merge branch 'develop' of https://github.com/ctjong/whiteboard-interviewer into develop
minor stuffs
Reverted InputValdator + test
Change date with datetime

now the date format is Y-m-d H:i:s