Counteract alignments and BTreeSets

[Kerollmops]

Think about BTreeSet heaviness.

[Kerollmops]

Not really interesting 9032965

$> cargo benchcmp old actual --variance --threshold 10
 name                                                                            old ns/iter       actual ns/iter    diff ns/iter   diff %
 board::tests::cant_place_on_double_free_threes                                  222 (+/- 147)     284 (+/- 96)                62   27.93%
 board::tests::counteract_alignment_by_breaking                                  598 (+/- 519)     1,214 (+/- 233)            616  103.01%
 board::tests::counteract_alignment_with_last_capture                            5,960 (+/- 898)   8,262 (+/- 3011)         2,302   38.62%
 board::tests::counteract_multiple_alignments_by_breaking                        1,185 (+/- 742)   2,522 (+/- 878)          1,337  112.83%
 board::tests::double_free_threes_cant_counteract_alignment                      7,111 (+/- 7111)  8,582 (+/- 2765)         1,471   20.69%
 board::tests::placement_do_nothing                                              207 (+/- 163)     317 (+/- 488)              110   53.14%
 functions::alignments::tests::alignments_diagonal_up_backward                   2 (+/- 1)         3 (+/- 1)                    1   50.00%
 functions::alignments::tests::alignments_diagonal_up_forward                    2 (+/- 4)         3 (+/- 6)                    1   50.00%
 functions::alignments::tests::alignments_horizontal_backward_and_forward        10 (+/- 17)       8 (+/- 2)                   -2  -20.00%
 functions::alignments::tests::alignments_horizontal_forward                     9 (+/- 1)         10 (+/- 9)                   1   11.11%
 functions::alignments::tests::alignments_list_all                               61 (+/- 13)       69 (+/- 25)                  8   13.11%
 functions::alignments::tests::alignments_list_all_too_small                     54 (+/- 8)        68 (+/- 33)                 14   25.93%
 functions::alignments::tests::alignments_vertical_forward                       19 (+/- 25)       21 (+/- 5)                   2   10.53%
 functions::captures::tests::captures_all                                        40 (+/- 17)       31 (+/- 45)                 -9  -22.50%
 functions::captures::tests::captures_bot                                        18 (+/- 4)        14 (+/- 32)                 -4  -22.22%
 functions::captures::tests::captures_bot_bounds                                 26 (+/- 50)       22 (+/- 41)                 -4  -15.38%
 functions::captures::tests::captures_bot_left                                   17 (+/- 20)       14 (+/- 37)                 -3  -17.65%
 functions::captures::tests::captures_bot_left_bounds                            25 (+/- 8)        33 (+/- 12)                  8   32.00%
 functions::captures::tests::captures_bot_right                                  16 (+/- 12)       18 (+/- 6)                   2   12.50%
 functions::captures::tests::captures_bot_right_bounds                           26 (+/- 10)       33 (+/- 11)                  7   26.92%
 functions::captures::tests::captures_left                                       16 (+/- 14)       14 (+/- 36)                 -2  -12.50%
 functions::captures::tests::captures_left_bounds                                26 (+/- 34)       23 (+/- 52)                 -3  -11.54%
 functions::captures::tests::captures_right_and_bot                              16 (+/- 9)        18 (+/- 5)                   2   12.50%
 functions::captures::tests::captures_right_bounds                               22 (+/- 13)       28 (+/- 12)                  6   27.27%
 functions::captures::tests::captures_top                                        14 (+/- 13)       19 (+/- 7)                   5   35.71%
 functions::captures::tests::captures_top_bounds                                 22 (+/- 20)       31 (+/- 12)                  9   40.91%
 functions::captures::tests::captures_top_left                                   15 (+/- 32)       19 (+/- 13)                  4   26.67%
 functions::captures::tests::captures_top_right_bounds                           24 (+/- 17)       30 (+/- 24)                  6   25.00%
 functions::captures_on_alignement::tests::captures_on_alignement_diagonal_down  874 (+/- 2555)    750 (+/- 872)             -124  -14.19%
 functions::captures_on_alignement::tests::captures_on_alignement_diagonal_up    402 (+/- 172)     759 (+/- 273)              357   88.81%
 functions::captures_on_alignement::tests::captures_on_alignement_horizontal     598 (+/- 418)     694 (+/- 325)               96   16.05%
 functions::free_threes::tests::double_free_three_horizontal_and_diagonal_down   48 (+/- 42)       63 (+/- 16)                 15   31.25%
 functions::free_threes::tests::double_free_three_horizontal_and_vertical        48 (+/- 38)       62 (+/- 15)                 14   29.17%
 functions::free_threes::tests::not_six_free_three_diagonal_down                 248 (+/- 98)      365 (+/- 169)              117   47.18%
 functions::free_threes::tests::not_six_free_three_vertical                      267 (+/- 192)     383 (+/- 102)              116   43.45%