[Vimpulse] Arrow keys don't work as motions

[Vegard Øye]

Hi Nick, thanks for the bug report.

This should be fixed in commit [9d7095a742]. Vimpulse compares the key
sequence as a string against shortcuts like "g??", but not all key
sequences can be represented as strings. String conversion can only
work if all the elements in the sequence are characters (i.e.,
integers). If not, we have to use vector format instead.

-- 
Vegard