[R] upgrading issues with Rcpp

[arnaud gaboury]

gabx at hortensia [R] sessionInfo()
R version 3.1.2 (2014-10-31)
Platform: x86_64-unknown-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
LC_MONETARY=en_US.UTF-8
 [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C
               LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] utils base

loaded via a namespace (and not attached):
[1] tools_3.1.2
--------------------------------------------------------------------

gabx at hortensia [R] search()
[1] ".GlobalEnv"    "tools:rstudio" "package:utils" "package:base"
--------------------------------------------------

Now when trying to update Rcpp:

gabx at hortensia [R] install.packages("Rcpp")
.............
Error in unloadNamespace(pkg_name) :
  namespace ‘Rcpp’ is imported by ‘reshape2’, ‘plyr’, ‘dplyr’ so
cannot be unloaded
......................

I can't upgrade my packages because of Rcpp >=0.11.3 needed (running
actually 0.11.2)

What is this namespace imported by  'reshape2’, ‘plyr’, ‘dplyr’ ? How
can I get rid of it and upgrade my packages ?

Thank you for hints
-- 

google.com/+arnaudgabourygabx