title: unable to install gganimate package from Github, both automatically and manually
body: <p>I am currently trying to install the gganimate package but seem unable to.
  I am running Win 10, Rx64 3.3.0 and Rstudio 0.99.896;
  the following command:</p>
  
  <pre><code>devtools::install_github("dgrtwo/gganimate")
  </code></pre>
  
  <p>will throw this error:</p>
  
  <pre><code>Downloading GitHub repo dgrtwo/gganimate@master
  from URL https://api.github.com/repos/dgrtwo/gganimate/zipball/master
  Error in curl::curl_fetch_memory(url, handle = handle) : 
    Problem with the SSL CA cert (path? access rights?)
  </code></pre>
  
  <p>So after a few hours of despair, I decided to try and install the package manually. I followed this link:
  <a href="https://stackoverflow.com/questions/14806705/manually-downloading-and-installing-packages-in-r?lq=1">here</a></p>
  
  <p>the following command:</p>
  
  <pre><code>install.packages(pkgs = "C:/Users/Superzucca/Desktop/gganimate-master.zip", repos = NULL)
  </code></pre>
  
  <p>results in:</p>
  
  <pre><code>    Installing package into ‘C:/Users/Superzucca/Documents/R/win-library/3.3’ 
  (as ‘lib’ is unspecified)
  </code></pre>
  
  <p>but then when I call:</p>
  
  <pre><code>library("gganimate-master") ####  -&gt; as suggsted by R itself!! 
  </code></pre>
  
  <p>this error is thrown:</p>
  
  <pre><code>Error in library("gganimate-master") : there is no package called ‘gganimate-master’
  </code></pre>
  
  <p>please, help. I don't have any problems installing other pkgs and honestly don't know what else to try.
  Thank you in advance,
  Superzucca</p>