title: when i use boost::archive::binary_iarchive , the error occur :invalid signature
body: <p>when i want to compile the program--cvpr_2012_ffd.you can get it from <a href="http://blog.gimiatlicho.webfactional.com/?page_id=38.I" rel="nofollow">http://blog.gimiatlicho.webfactional.com/?page_id=38.I</a> compile the program according to it's README.
     when I run this program that I encounter some error.the error is this</p>
  
  <p>Image pathdata/index_random_subset.txt
  paths to treesdata/trees_ffd/
  Image path 
  paths to treesdata/trees_headpose/tree_
  10 to load.
  Archive Exception during deserializing:
  invalid signature
  it was tree: data/trees_headpose/tree_000.txt
  segment fault</p>
  
  <p>I find this error appear in the file:tree.hpp
  the code like this </p>
  
  <pre><code>224     //check if file exist
  225     std::ifstream ifs(path.c_str());
  226     if (!ifs) {
  227       std::cout &lt;&lt; "Tree not found " &lt;&lt; path &lt;&lt; std::endl;
  228       return false;
  229     }
  230 
  231     //load tree
  232     try {
  233 //      boost::archive::binary_iarchive ia(ifs);
  234       boost::archive::binary_iarchive ia(ifs);
  235       ia &gt;&gt; *t;
  236     } catch (boost::archive::archive_exception&amp; ex) {
  237       std::cout &lt;&lt; "Archive Exception during deserializing:" &lt;&lt; std::endl;
  238       std::cout &lt;&lt; ex.what() &lt;&lt; std::endl;
  239       std::cout &lt;&lt; "it was tree: " &lt;&lt; path &lt;&lt; std::endl;
  240     } catch (int e) {
  241       std::cout &lt;&lt; path &lt;&lt; "EXCEPTION " &lt;&lt; e &lt;&lt; std::endl;
  242 
  243     }
  </code></pre>
  
  <p>the error occur in the line:234</p>
  
  <p>Do somebody encounter this error?how to solve this problem ?thanks</p>