A fully functional release

The following changes have been made,

• Activate package logo for the GitHub repository.
• Dedicated .R files for (blocks of) functions.
• Use of scope operator for clarification, e.g., ensembldb::genes().
• Use of OPENGWAS_JWT from https://api.opengwas.io/profile/.
• Suggest IlluminaHumanMethylation450kmanifest, OUTRIDER.
• Fix URL in DESCRIPTION/snakemake.Rmd.

In particular, it is equipped with

• bookdown and ifunctional interactive graphcs,
• TwoSampleMR-under the new authentication scheme.

Full Changelog: 0.2...0.3

0.2

pQTLtools 0.2

This is a major release, including revision and validation of elementrs in the package and R CMD check --as-cran.