Fix Calendar to handle keypress events forwarded from !DateTextBox, thus making the  !DateTextBox's calendar drop down keyboard accessible.
Fix Calendar to handle keypress events forwarded from !DateTextBox, thus making the  !DateTextBox's calendar drop down keyboard accessible.

Needs review for screen reader support (if that's possible to support).   One possible modification is to make every keystroke change the value in the <input> field, so that the screen reader knows what happened.

Also, need to add automated tests (after the a11y review).

Fixes #6416 !strict.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@22556 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful