Insilicoseq

iss generate`:
- `--genomes` accepts multiple input files
- new, optional `--draft` option for input draft genomes (71)
- now accepts combinations of --genomes, --draft and --ncbi
- new --seed argument for reproducibility (75)
- consistent number of reads (74)

`minor fixes`
- upgrade requests in `Pipfile.lock`

This is a bug fix release:

- `iss`: now works with python 3.7 (68)
- `iss generate`: minor change to the read names to make BWA happy (67 , thanks alienzj for the PR 🎉 )
- `iss model`: Do not crash on weird CIGAR strings anymore (69)
- `iss model`: aligned reads can now be of different lengths

- Now supports an optional `--coverage` argument to produce abundance profiles based on coverage information instead of abundance
- Improved documentation
- Fix for 64

- Fix 59
- Switch to pipenv for development
- Small changes to documentation

This patch release contains bug fixes and documentation improvements

- `--n_genomes` works again with the `--ncbi` option
- the examples in the documentation should be more clear

This release introduces the possibility to use `--n_genomes`/`-u` with `--genomes`

In other words, you can now generate reads from a random subset of a multifasta file 🎉