title: R base function to sort vector of strings based on length
body: <p>I was wondering if there is an already made function in R base package that can sort a vector of strings taking into consideration the length of each element and then of course the lexicographical order. 
  For instance after a <em>sort</em> call on some vector holding age groups you would have:</p>
  
  <pre><code>v &lt;- c("00-04", "05-09", "10-14", "100-104", "105-109", "110-114", "15-19", "20-24"..etc)
  </code></pre>
  
  <p>whereas I would like to have:</p>
  
  <pre><code>v &lt;- c("00-04", "05-09", "10-14", "15-19", "20-24"..etc.. "100-104", "105-109", "110-114")
  </code></pre>