def match_all(data, &block)
      return nil if @root == nil
      i=0
      while (i<data.length)
        node = @root.find_forward(data, i, data.length-i)
        if (node!=nil && node.value!=nil)
          yield Item.new(i, true, node)
          i += node.length
        else
          i += 1
        end
      end
    end
def match_all(data, &block)
      return nil if @root == nil
      i=0
      while (i<data.length)
        node = @root.find_forward(data, i, data.length-i)
        if (node!=nil && node.value!=nil)
          yield Item.new(i, true, node)
          i += node.length
        else
          i += 1
        end
      end
    end
Tokenize the string Data by finding all instances of any key in the Tree.
 yields each instance as a StringTree::Item.