Misc. typos

Some are doxy comments, some are just trivial source comment typos. 
Found using `codespell -q 3 --skip="./contrib" -I ../assimp-whitelist.txt`
whereby whitelist contained:
```
childs
iff
lod
nto
ot
whitespaces
```

code/TextureTransform.cpp

@@ -317,7 +317,7 @@ void TextureTransformStep::Execute( aiScene* pScene)
                     info.lockedPos = AI_TT_UV_IDX_LOCK_TBD;
                 }
 
-                // Get all coresponding meshes
+                // Get all corresponding meshes
                 for (unsigned int n = 0; n < pScene->mNumMeshes;++n)    {
                     aiMesh* mesh = pScene->mMeshes[n];
                     if (mesh->mMaterialIndex != i || !mesh->mTextureCoords[0])