Percent bases below cutoffs

[dariober]

It would be useful to report the percent bases below given quality cutoffs. Like:

fxstats -B 5,10,20 in.fq

n_seq              13962380
n_bases            1047588337
mean_length        75.03
median_length      76.00
mean_read_quality  26.05
bases_below_Q5      1.23%
bases_below_Q10     10.3%
bases_below_Q20     20.3%
...

Useful to know how much data we throw away when filtering for base quality.

Basically we need an array similar to nt_counter in struct results. We iterate through the quality string and increment the corresponding char.

long baseq_counter[NCHARS] = {0};

// In function scan_file add
count_nt(seq->quality.s, seq_len, results->baseq_counter);