Keyboard mapping in the interface is behaving incorrectly

[mattprintz]

We need a full review of keyboard mapping and behavior, as several features that once worked no longer do.

Here are a few items that have been observed, but is not a full list:

• Pressing up while editing a prompt that has overflown to the more than one line causes the selection of the last cell. Jumping from the text input to cell should only happen if the cursor is already at position 0. (If you push up while somewhere on the top line, it should jump to the beginning of the text block.)
• Pressing down to select a autocomplete suggestion breaks out of the autocomplete dropdown.
• Pressing tab when an autocomplete suggestion is hightlighted should select and fill the completion, not indent the text or jump ahead in the line

There are likely other issues that also need to be addressed.