Added explicit calls to fstream::close rather than relying on destructors as a tentative gcc-cygwin fix.

[SVN r21287]

example/snippets/regex_split_example_2.cpp

@@ -55,6 +55,7 @@ int main(int argc, char** argv)
       s.erase();
       std::ifstream is(argv[i]);
       load_file(s, is);
+      is.close();
       boost::regex_split(std::back_inserter(l), s, e);
       while(l.size())
       {
@@ -74,6 +75,7 @@ int main(int argc, char** argv)
       s.erase();
       std::ifstream is(argv[i]);
       load_file(s, is);
+      is.close();
       while(boost::regex_split(std::ostream_iterator<std::string>(std::cout), s, e, boost::match_default, 1)) std::cout << std::endl;
    }