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/OgreMaterial.cpp

@@ -258,7 +258,7 @@ aiMaterial* OgreImporter::ReadMaterial(const std::string &pFile, Assimp::IOSyste
                 ReadTechnique(Trim(techniqueName), ss, material);
             }
 
-            // Read informations from a custom material
+            // Read information from a custom material
             /** @todo This "set $x y" does not seem to be a official Ogre material system feature.
                 Materials can inherit other materials and override texture units by using the (unique)
                 parent texture unit name in your cloned material.