Support for QSEQ parsing.

This relates to issue #389.  @audy, @wasade.

Added parse_qseq, QseqIterator, support in the factory for .qseq and .qseq.gz.  Added unit tests.

For Sequence ID, I am using: "machine_name"_"run_number":"lane_number":"tile_number":"x":"y"#"index"/"read".  Example: CRESSIA_242:1:2204:1453:1918#0/1.  Do you agree?

I set qual_id to seq_id.  Do you agree?


This will cause Python 3 issues which are described further in [here](https://github.com/biocore/scikit-bio/blob/master/doc/source/development/py3.rst) including how to resolve. Basically, you can import from `future`