title: Package dependency error "there is no package called ‘stringi’"
body: <p>I created an R package and loaded it to github (<a href="https://github.com/lucasmation/microdadosBrasil" rel="nofollow">microdadosBrasil</a>). When I try to install the package (as a user would) I get the following error: </p>
  
  <pre><code>devtools::install_github("lucasmation/microdadosBrasil")
  Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) : 
    there is no package called ‘stringi’
  </code></pre>
  
  <p>I tried solving this by adding <strong>stringi</strong> to the package dependencies 
  In DESCRIPTION in included: </p>
  
  <pre><code>Imports:
      stringi
  </code></pre>
  
  <p>I also included the package import at NAMESPACE</p>
  
  <pre><code>import(stringi)
  </code></pre>
  
  <p>But, even then I get the same installation error. 
  To be hones I'm not even aware of any explicit function in my package that uses the <code>stringi</code> package. </p>
  
  <p>If I install <code>stringi</code> before then the <code>microdadosBrasil</code> installation works: </p>
  
  <pre><code>install.packages('stringi')
  devtools::install_github("lucasmation/microdadosBrasil")
  </code></pre>
  
  <p>This is the session information when error occurs (before pre-installing  <code>stringi</code>)</p>
  
  <pre><code>sessionInfo()
  R version 3.1.3 (2015-03-09)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows 7 x64 (build 7601) Service Pack 1
  
  locale:
  [1] LC_COLLATE=Portuguese_Brazil.1252  LC_CTYPE=Portuguese_Brazil.1252   
  [3] LC_MONETARY=Portuguese_Brazil.1252 LC_NUMERIC=C                      
  [5] LC_TIME=Portuguese_Brazil.1252    
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  loaded via a namespace (and not attached):
  [1] tools_3.1.3
  </code></pre>