Centers may be only recalculated when current_good_n >= N_cov_points

[Jonathan Ozik]

https://github.com/c-rutter/imabc/blob/master/R/imabc.R#L770

Example output to show the issue:

grep "New in range draws =\|Removing\|---------- Start Iter" output.txt
---------- Start Iter 1 ----------
New in range draws = 0
---------- Start Iter 2 ----------
New in range draws = 2
---------- Start Iter 3 ----------
New in range draws = 2
---------- Start Iter 4 ----------
New in range draws = 4
---------- Start Iter 5 ----------
New in range draws = 5
---------- Start Iter 6 ----------
New in range draws = 7
---------- Start Iter 7 ----------
New in range draws = 7
---------- Start Iter 8 ----------
New in range draws = 11
---------- Start Iter 9 ----------
New in range draws = 12
---------- Start Iter 10 ----------
New in range draws = 13
---------- Start Iter 11 ----------
New in range draws = 19
---------- Start Iter 12 ----------
New in range draws = 23
---------- Start Iter 13 ----------
New in range draws = 28
---------- Start Iter 14 ----------
New in range draws = 29
---------- Start Iter 15 ----------
New in range draws = 32
---------- Start Iter 16 ----------
New in range draws = 38
---------- Start Iter 17 ----------
New in range draws = 41
---------- Start Iter 18 ----------
New in range draws = 46
---------- Start Iter 19 ----------
New in range draws = 53
Removing centers as good draws: 5509, 8757, 10140, 10982, 11963, 15834, 16719, 17138, 18005, 18470 
---------- Start Iter 20 ----------
New in range draws = 48
---------- Start Iter 21 ----------
New in range draws = 50
Removing centers as good draws: 2615, 5207, 6218, 15449, 17816, 18431, 19030, 19203, 19271, 19360 
---------- Start Iter 22 ----------
New in range draws = 43
---------- Start Iter 23 ----------
New in range draws = 50
Removing centers as good draws: 5215, 11554, 14696, 18392, 21073, 21315, 21664, 21954, 22398 
---------- Start Iter 24 ----------
New in range draws = 45
---------- Start Iter 25 ----------
New in range draws = 48
---------- Start Iter 26 ----------
New in range draws = 53
Removing centers as good draws: 11279, 13683, 17673, 22581, 23453, 23732, 24121, 25005, 25150, 25466