title: Cannot install RStudio addins on my Windows laptop from behind proxy
body: <p>My session info (basically it's Microsoft R Open 3.4.1, RStudio 1.0.153, Windows 10 64 bit)</p>
  
  <pre><code>&gt; sessionInfo()
  R version 3.4.1 (2017-06-30)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows &gt;= 8 x64 (build 9200)
  
  Matrix products: default
  
  locale:
  [1] LC_COLLATE=English_United States.1252 
  [2] LC_CTYPE=English_United States.1252   
  [3] LC_MONETARY=English_United States.1252
  [4] LC_NUMERIC=C                          
  [5] LC_TIME=English_United States.1252    
  
  attached base packages:
  [1] stats     graphics  grDevices utils    
  [5] datasets  methods   base     
  
  other attached packages:
  [1] RevoUtilsMath_10.0.1
  
  loaded via a namespace (and not attached):
   [1] httr_1.3.1       compiler_3.4.1  
   [3] R6_2.2.0         RevoUtils_10.0.6
   [5] tools_3.4.1      withr_2.0.0     
   [7] curl_2.6         memoise_1.1.0   
   [9] git2r_0.19.0     digest_0.6.12   
  [11] devtools_1.13.3 
  </code></pre>
  
  <p>I'm trying to install some <a href="https://rstudio.github.io/rstudioaddins/" rel="nofollow noreferrer">RStudio addins</a> without success. Whatever addin I try to install, the recommended procedure of using <code>devtools::install_github</code> (see <a href="https://rstudio.github.io/rstudioaddins/#installation" rel="nofollow noreferrer">Installation</a>) fails with the same error message:</p>
  
  <pre><code>&gt; devtools::install_github("benmarwick/wordcountaddin", type = "source", dependencies = TRUE)
  Installation failed: Failure when receiving data from the peer
  &gt; devtools::install_github("rstudio/addinexamples", type = "source")
  Installation failed: Failure when receiving data from the peer
  </code></pre>
  
  <p>I work behind a company proxy. I am able to install R packages from CRAN without problems:</p>
  
  <pre><code>&gt; install.packages("devtools")
  Installing package into ....
  (as ‘lib’ is unspecified)
  trying URL 'https://mran.microsoft.com/snapshot/2017-09-01/bin/windows/contrib/3.4/devtools_1.13.3.zip'
  Content type 'application/zip' length 443758 bytes (433 KB)
  downloaded 433 KB
  
  package ‘devtools’ successfully unpacked and MD5 sums checked
  
  The downloaded binary packages are in
  ....
  </code></pre>
  
  <p>How can I install RStudio addins?</p>