Update of two headers
Littles fixes

-Light Manager: I prefer iterators
-OpenGL: The UV problem is solved, but you forget to change the cubemaps
-Texture: GetSize() could return a int instead a NzVector2ui
-Algorithm: Simplification
-Utility: Couldn't compile
Writing style file

Add of a file for the standard writing in the project.
I think it could be helpful.
Merge pull request #31 from Gawaboumga/master

Some changes