Fixed build warnings on MSVC14 x64 in the MS3D format sources.

code/MS3DLoader.cpp

@@ -423,7 +423,7 @@ void MS3DImporter::InternReadFile( const std::string& pFile,
         for (unsigned int i = 0; i < groups.size(); ++i) {
             TempGroup& g = groups[i];
             if (g.mat == UINT_MAX) {
-                g.mat = materials.size()-1;
+                g.mat = static_cast<unsigned int>(materials.size()-1);
             }
         }
     }
@@ -483,7 +483,7 @@ void MS3DImporter::InternReadFile( const std::string& pFile,
         m->mMaterialIndex  = g.mat;
         m->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
 
-        m->mFaces = new aiFace[m->mNumFaces = g.triangles.size()];
+        m->mFaces = new aiFace[m->mNumFaces = static_cast<unsigned int>(g.triangles.size())];
         m->mNumVertices = m->mNumFaces*3;
 
         // storage for vertices - verbose format, as requested by the postprocessing pipeline