Implement DESCRIPTION file guidance

[gregorgorjanc]

As per https://contributor.r-project.org/cran-cookbook/description_issues.html and e-mail that I received from CRAN.

• quote packages (we do this), but also Python, C, AND R?! (really?) https://contributor.r-project.org/cran-cookbook/description_issues.html#solution - waiting for CRAN feedback (if we will get it!?)
• remove license? We signal clearly who is doing what so I think we need them!? https://contributor.r-project.org/cran-cookbook/description_issues.html#solution-2
• https://contributor.r-project.org/cran-cookbook/description_issues.html#solution-5