Fix unwanted GET {0} requests

Because of image prefetch of browsers the <img src="{0}"> templates cause
unwanted /{0} requests to the webserver. Templates are changed to use a
data-src attribute.
Also for notifications.
bring the posted-date selector widget up to date. There are no longer two different styles.
Merge https://github.com/friendica/red into pending_merge
Merge pull request #439 from oohlaf/fixes

Fix unwanted GET {0} requests
Merge https://github.com/friendica/red into pending_merge
allow birthdays with just a year (no month or day).