Iterator over arrays when calculate draw variable
Iterator over arrays when calculate draw variable

When array appears as branch value, one iterate over all its values to
calculate draw variable values. When several arrays are used in draw
variable, loop limited by minimal array length. 
Not clear, that to do when empty array appears
bellenot/jsroot,root-project/jsroot,bellenot/jsroot,linev/jsroot,linev/jsroot,root-project/jsroot,bellenot/jsroot