Add example: load and display texture on quad

[Nicolas Mellado]

There is currently no example showing how to load a texture from a file, can we add a single-file demo doing that ?

[Mathias Paulin]

Not sure to understand what you're asking for. The texture manager offers all what is needed for that. The documentation says how to load a texture from a file (even if the doc could be improved in its form and content, the main objectives are covered). See getOrLoadTexture, loadTexture and loadTextureImage

[David Vanderhaeghe]

closed by #890