[Rd] --vanilla option for creating cluster nodes

[Richard Cotton]

When a PSOCK cluster (maybe other cluster types too) is created by the
parallel package, an Rscript process is spawned for each node.  At
least by default, the Rprofile.site file is read for each node that is
created, which can constitute the majority of the time to create a
cluster.  See:

http://stackoverflow.com/q/23540129/134830

Is there a way to create nodes using the --vanilla argument, so that
Rprofile doesn't get read?

Alternatively, is there a way to persuade R to only read the file
once?  It seems inefficient to do the same thing four times.