[datepicker] Reuse same calendar for all datepickers
Merge pull request #1506 from pjackson28/v3.0

Added ISO 639-2/T codes to i18n in addition to the ISO 639-1 codes (to support requirements for dcterms.language)
Merge branch 'v3.0' of https://github.com/wet-boew/wet-boew into issue1456
Merge pull request #1510 from berubs/issue1456

[datepicker] Reuse same calendar for all datepickers
Fixes gh-1456
Resolved merge conflict.