Need support for Rectangle operations

[okia]

Any realistic Emacs workflow inevitably comprises Rectangle operations. We should be able to support at least the following Rectangle-related keybindings:

Keybinding	Description
C-x r r	Copy rectangle to register
C-x r k	Kill rectangle
C-x r y	Yank rectangle
C-x r o	Open rectangle, shifting text right
C-x r c	Blank out rectangle
C-x r t	Replace rectangle contents with string on each line

[okia]

FYI: looking into it... On relevant note, what is the procedure and/or protocol for becoming an assignee (for particular issue)?