Augmented paragraph movement commands

Augmented paragraph movement commands

Move by paragraph by default, but by block with C-u prefix.

The addition of the separate keybindings M-[ and M-] for movement by
block was problematic because the escape sequences sent for the delete
key by some keyboards begin with M-[.  When running in the terminal,
this causes Emacs to trigger the block movement command and insert a
control character (corresponding to the remainder of the sequence).

To remedy this situation, the specific M-[ and M-] block movement
keybindings have been removed.  Instead, the usual M-{ and M-} paragraph
movement commands have been augmented: skip by paragraphs, as defined,
or by block when the C-u prefix is given.

Some relevant Emacs history:

> M-[ was an Emacs 18 binding which was moved to M-{ in Emacs 19,
> precisely because it conflicted with the escape sequences produced by
> some common keyboards.

Source: <http://www.nongnu.org/emacs-tiny-tools/keybindings/index-body.html>