rpy2-r6

Extension package for rpy2 to faciliate the handling of R6 objects (R6 is an OOP system for R).

(an earlier proof-of-concept was in @matthewwardrop's PR on bitbucket - https://bitbucket.org/rpy2/rpy2/pull-requests/73 - and this is a proposed-yet-currently incomplete evolution of it)

An HTML build of the documention in is available from the rpy2 project pages: https://rpy2.github.io/r6_doc.html