title: R install package loaded namespace
body: <p>I would like to install the package plotly in RStudio and got a error message.  </p>
  
  <p><code>install.packages("~/Desktop/plotly_4.5.2.tar.gz", repos = NULL, type = "source")</code></p>
  
  <blockquote>
    <p>Error in loadNamespace(j &lt;- i[[1L]], c(lib.loc, .libPaths()),
    versionCheck = vI[[j]]) :    namespace ‘Rcpp’ 0.12.3 is already
    loaded, but >= 0.12.7 is required.</p>
  </blockquote>
  
  <p><code>packageVersion('Rcpp')</code><br>
  I checked the version of Rcpp and it is 0.12.13 version, but the loaded version is 0.12.3 when installing the package. Is there any way to load the 0.12.13 version from library path when install the package? </p>