M-b and M-f maps move 'word' instead of 'WORD'

This is a continuation of discussion in #20.
I think I managed to get reliable `M-b` and `M-f` that move across 'words' in
cli.

I *think* the implementation is not that horrible.
The functions could probably be trimmed down or maybe merged to just one func
somehow.
But, since my intention is to get feedback for now, I left it as-is.

Let me know what you think!