Add a 'cycle' option to direction

This allows to loop on a file list, going at the other side of the list when trying to go beyond the boundaries (e.g. pressing down when the last file is selected). 

Test command: `move up=1 cycle=true`

Note: in `minimum + pos % (maximum + offset - minimum)`, I am not sure if the use of 'offset' is appropriate (i.e. not sure whether it is broken or not).