Math bindings

[Dekel Tsur]

Typing 'M-m f' generates 'rac' (ERT) on screen.
Same problem with the other bindings.

An unrelated bug: When creating a new macro, LyX puts ^@ at the end of the
definition, namely when you save the file, the result is
 \newcommand{\foo}{foo^@}
instead of
 \newcommand{\foo}{foo}

The ^@ char is invisible on the LyX screen (but it can be deleted).