update new in release doc
pipe implementation

after trying magrittr in detail, back to owning the implementation.
kill some residual <-
switch to .., fix some eval aspects
simplified special var .. detection
explain what vectorized grouping does and relation to extend
move magic wand example. Explain interaction with vectorization.
move magic wand example. Explain interaction with vectorization.
explain what vectorized grouping does and relation to extend
Merge branch 'dev'

decided to pull in the latest as there is a little delay in releasing rmr2.
rename to testing to avoid suggesting incompatibility
updated special var .. and dependency
evicted magrittr, refresh, .. rename