Fixed example in the API doc of sf::SocketSelector
Disabled fix #271 for ogg cracks (the solution slows down the loading too much)
Improved the success message in FindSFML.cmake
Minor modification to the API documentation
Fixed the repeated keys detection algorithm on Linux
Fixed computation of the alpha channel in sf::BlendAdd
Changed Texture::bind and Shader::bind to be static functions, that can accept a null argument