Separate error message into warning and error. Breaks API, so bump to version 1.3.0

examples/obj_sticher/obj_sticher.cc

@@ -1,11 +1,10 @@
 //
 // Stiches multiple .obj files into one .obj.
 //
-
-#define TINYOBJLOADER_IMPLEMENTATION
-#include "../../tiny_obj_loader.h"
 #include "obj_writer.h"
 
+#include "../../tiny_obj_loader.h"
+
 #include <cassert>
 #include <iostream>
 #include <cstdlib>
@@ -134,8 +133,9 @@ int main(int argc, char **argv)
   for (int i = 0; i < num_objfiles; i++) {
     std::cout << "Loading " << argv[i+1] << " ... " << std::flush;
     
+    std::string warn;
     std::string err;
-    bool ret = tinyobj::LoadObj(&attributes[i], &shapes[i], &materials[i], &err, argv[i+1]);
+    bool ret = tinyobj::LoadObj(&attributes[i], &shapes[i], &materials[i], &warn, &err, argv[i+1]);
     if (!err.empty()) {
       std::cerr << err << std::endl;
     }