Update demo.js
Update demo.js

Added code to give an example of 'singleDate' option with two months view and one month view.
longbill/jquery-date-range-picker,dsgraham/jquery-date-range-picker,dsgraham/jquery-date-range-picker,longbill/jquery-date-range-picker,fede91it/jquery-date-range-picker,fede91it/jquery-date-range-picker