added C++ to xCycle
fixed a crashing error.
removed C++, as R code is vectorised.
working on powerset
working on C++ powerset
updated example
attempting to fix missing univerrsal methods.
added news
fixed failing tes
flagged xDelay as having an uncertain future.
updated xZipKeys in C++
removed a comment.
added comments.
updated c
rewrote c++ in riffle.
updated news.
Merge branch 'develop' into releases