- Added new css selector "calendar-cell-selected" for selected date.
- Date picker popup always opens either on selected date or today date.
Revert "- Added new css selector "calendar-cell-selected" for selected date. - Date picker popup always opens either on selected date or today date."

This reverts commit 9b528bc784409048aeca80cf8c4a5e23d8ace62f.
- Added new css selector "calendar-cell-selected" for selected date.
- Date picker popup always opens either on selected date or today date.
Merge pull request #3 from Asapin/master

Selected date can be highlighted using CSS.