code: function(start, end, step) { // 用于生成整数数组
              step || (step = 1)
              if (end == null) {
                  end = start || 0
                  start = 0
              }
              var index = -1,
                      length = Math.max(0, Math.ceil((end - start) / step)),
                      result = Array(length)
              while (++index < length) {
                  result[index] = start
                  start += step
              }
              return result
          }
docs: /* avalon.range(10)
  => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
  avalon.range(1, 11)
  => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
  avalon.range(0, 30, 5)
  => [0, 5, 10, 15, 20, 25]
  avalon.range(0, -10, -1)
  => [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
  avalon.range(0)
  => []