make benchmark ruby 2.1 compatible; add sort benchmark for huge collection

collection with one million items

                          RUBY | COMB_SORT | HEAPSORT | INSERTION_SORT
| SHELL_SORT | QUICKSORT | MERGESORT |
------------------------------------------------------------------------
-------------------------------------
Already sorted           0.001 |     0.441 |  540.654 |          0.015
|      0.191 |   153.021 |     0.278 |
Random                   0.015 |     0.650 |  591.552 |        194.811
|      0.332 |     0.153 |     0.385 |