make tracebugs tempfiles multiuser safe
Merge pull request #56 from hredestig/master

make tracebugs tempfiles multiuser safe
delete temp files in R and make tmp files unique

   Completes the fix for #56
updating ESSR version/archive
call getCRANmirrors with local.only

   sometimes cran is down and it is inconvenient
don't visit DESCRIPTION file when detecting package path

  ess-developer was closing DESCRIPTION silently before
completion works again in ess-execute
todo