title: Is it possible to use spread on multiple columns in tidyr similar to dcast?
body: <p>I have the following dummy data: </p>
  
  <pre><code>library(dplyr)
  library(tidyr)
  library(reshape2)
  dt &lt;- expand.grid(Year = 1990:2014, Product=LETTERS[1:8], Country = paste0(LETTERS, "I")) %&gt;%   select(Product, Country, Year)
  dt$value &lt;- rnorm(nrow(dt))
  </code></pre>
  
  <p>I pick two product-country combinations</p>
  
  <pre><code>sdt &lt;- dt %&gt;% filter((Product == "A" &amp; Country == "AI") | (Product == "B" &amp; Country =="EI"))
  </code></pre>
  
  <p>and I want to see the values side by side for each combination. I can do this with <code>dcast</code>:</p>
  
  <pre><code>sdt %&gt;% dcast(Year ~ Product + Country)
  </code></pre>
  
  <p>Is it possible to do this with <code>spread</code> from the package <strong>tidyr</strong>?</p>