Update daterangepicker.js

Allow to send one date using customShortcuts so that shortcuts can me created to move calendars to a specific date than selecting a specific date range!
Update demo.js

extends customShortucts example by specifying a single date to allow shortcuts to move calendars to a specific date/month
minor english language corrections to less than, more than
Merge pull request #5 from unitedworx/master

Extended functionality of  customShortcuts