math/R: Update to version 3.3.2 and other changes

• Changes in version 3.3.2: https://cran.r-project.org/doc/manuals/r-release/NEWS.html

• Port Changes
  • Definitively set PORTNAME after removal of slave ports
  • Set MASTERS_SITES to CRAN
  • Make documentation installation simpler for users
    • make the DOCS option the only option for extra documentation (remove PDF option)
    • turn this option off by default since it pulls in over 1 GB of build dependencies (TeX and friends)
  • Do not make INFO option imply DOCS option
  • Cosmetic changes

Reviewed by: mat
Approved by: swills (mentor)
Differential Revision: https://reviews.freebsd.org/D8330