Taxadb

- makes it clear that `taxadb query` is not implemented (44 )
- `taxid.lineage_id` and `taxid.lineage_name` now return lists of tuples instead of dictionaries with the `ranks=True` option (46 )

Bugfix release

* This version bumps the `peewee` version number in `setup.py` to the correct version.

- adaptation to NCBI file structure changes (39 )
- minor performance improvements
- handles "Too many SQL variables" properly when building the database (4 )

- New `ranks` option that returns a dictionary when querying the lineage:

python
lineage = taxid.lineage_id(9986, ranks=True)
print(lineage)
{'species': 9986, 'genus': 9984, 'family': 9979, 'order': 9975, 'no rank': 131567,
'superorder': 314146, 'class': 40674, 'subphylum': 89593, 'phylum': 7711,
'kingdom': 33208, 'superkingdom': 2759}


- Can now create taxonomy only database (without accession numbers)

Add two functions calls:

* `has_parent` checks is a sci name or a taxid is part of the lineage of a organism
* `SciName.taxid` allows for querying the db for taxids using scientific names

A few improvements:

- now displays progress bars with `taxadb download` and chunks per second with `taxadb create`
- `taxadb download` now uses https instead of ftp

and the unfortunate:

- Prebuilt databases are no longer provided