Workaround incompatibilities with the keyboard setup of some vendors

Workaround incompatibilities with the keyboard setup of some vendors

Some vendors, like Debian (and therefore Ubuntu), enable smkx terminal
mode in the zle-line-init widget and turn it back off in
zle-line-finish.

While that is the right thing to do, because it makes sure the values
from $terminfo are valid. However, we are currently incompatible with
that. And it is a lot of work to get it right for every binding we have,
because we do have some, that are not available in the vast majority of
terminfo entries (like <Ctrl>-<CursorKey>).

Signed-off-by: Frank Terbeck <ft@grml.org>