Added close button to pickadate - this closes the modal without affecting the currently selected date

...d date.

Added .idea to gitignore to ignore JetBrains IDE config files
Executing grunt default caused jshint errors as some variables are not in use. Removed unused variables and now all tasks run fine
Encapsulated the creation of the 3 different sections of the calendar in picker.date.js
Resolved error in grunt file with addtional ',' added.