MINOR: Deleted reference to CalendarDateField.js
MINOR: Year validation (accept just 4 digit, like the error message says).
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/branches/2.4@97991 467b73ca-7a2a-4603-9d3b-597d59a354a9