addition to r580: *all* nls() calls (and updates) use slightly looser 
tol = 8e-8 now {currently needed for Mac OSX, also on CRAN}


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/robustbase@585 694ef91d-65df-0310-b7bb-92e67a308ead
export .MCDcons, .MCDcnp2{.rew}, and .MCDsingularityMSG, 
so Valentin does not need to use ":::" in rrcov[NA] packages.
Nicely wrapup the MCDncp2sim() functions as closures, i.e. functions with non-trivial environment

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/robustbase@586 694ef91d-65df-0310-b7bb-92e67a308ead