CRM-13966 - Add Select2.js and basic widget support
CRM-13966 - Convert adv search crmasmselect to select2
CRM-13966 - Convert campaign crmasmselect to select2 and support optgroups
CRM-13966 - Style select2 with search icon
CRM-13966 - Refactor out and remove crmasmselect
Merge pull request #2441 from colemanw/select2

Goodbye crmasmselect! Hello Select2