Clarifying activity of sample-reads-randomly.py in documentation

[brooksph]

The documentation states that the sample-reads-randomly.py will sample the number of sequences specified with -N, however, in the case of paired in reads it actually samples the number of pairs specified with -N.

For example, sample-reads-randomly.py -N 10800000 -M 100000000 -o SRR606249_subset10.fq.gz --gzip SRR606249.fq.gz samples 21600000 instead of 10800000 from the paired-end file SRR606249_subset10.fq.gz.

[standage]

Sorry I haven't responded to this earlier. If you wanted to submit a pull request with a correction to the documentation, that should be a fairly easy fix. I'd be happy to point you in the direction of the correct files if that would help!