Use the documented 5 line prolog in every sample application. Tidy up sample prologs and header code.

samples/httptest.cpp

@@ -23,7 +23,6 @@
  */
 
 #include <exiv2/exiv2.hpp>
-
 #include <iostream>
 #include <stdlib.h>
 
@@ -40,6 +39,9 @@ int main(int argc,const char** argv)
 {
     Exiv2::XmpParser::initialize();
     ::atexit(Exiv2::XmpParser::terminate);
+#ifdef EXIV2_ENABLE_BMFF
+    Exiv2::enableBMFF();
+#endif
 
     if ( argc < 2 ) {
         std::cout << "usage  : " << argv[0] << " [key value]+" << std::endl;