Revert "Make the default by-word movement stop at word boundaries, rather than word end"

This reverts commit dd919a2bcf93a59b2ab28aa766c50fe6e5d9d239.
By-word movement change, take 2: count groups of punctuation as words

Adds goGroupLeft/Right, delGroupLeft/Right as alternative to word-based
motion/deletion. Binds ctrl-left/right/del/backspace to these commands.

Also makes word and group-based motion stop at line boundaries.