Add module to convert multiple fastq files into a single file.

Add module to convert multiple fastq files into a single file.

The HiSeq likes to produce N seperate fastq files to simplify
parallel processing.

Also I decided to split out the parse_slice code into a
util module since it was being shared between the desplit_fastq
and qseq2fastq.

Finally just for fun I ran these two modules through pep8.py
and pylint.py and cleaned up those errors