@rotate(t:tab, n:int)
build a new tab which contains the elements of t circularly shifted by n. If n is positive the element are right shifted, else they are left shifted. 
       @rotate([1, 2, 3, 4], -1) == [2, 3, 4, 1]
       @rotate([1, 2, 3, 4], 1) == [4, 1, 2, 3]

See also Tab Manipulations @car,    @cdr,    @clear,    @concat,    @cons,    @copy,    @count,    @dim,    @domain,    @drop,    @empty,    @find,    @flatten,    @gnuplot,    @insert,    @iota,    @is_list,    @is_prefix,    @is_subsequence,    @is_suffix,    @lace,    @last,    @listify,    @map,    @max_val,    @median,    @member,    @normalize,    @occurs,    @parse,    @permute,    @push_back,    @push_front,    @range,    @reduce,    @remove,    @remove_duplicate,    @replace,    @reshape,    @resize,    @reverse,    @rotate,    @scan,    @scramble,    @size,    @slice,    @sort,    @sputter,    @stutter,    @succession,    @tab_history,    @tab_history_date,    @tab_history_rdate,    @take    @to_num