Add test description to README

[fgvieira]

Would it be possible to get a description of what the program checks for on the FASTQ files? For example:

• gzip file corrupted
• length of read and quality
• read IDs match on both R1 and R2 files
• number of reads on R1 and R2 files
• duplicated read IDs
• ...

thanks,

[sfchen]

Will try to implement these, thanks