Initial commit of 3D rendering prototype implementation for SFML.
Added sf::VertexBuffer, sf::VertexContainer, support for 1D and 3D textures, better support for checking what version of GLSL is available and made all drawable classes use sf::VertexContainer for geometry storage.
Added missing m_needUpload statement to non-const pointer getter in VertexBuffer.
Implemented non-legacy rendering for drawables, unified sf::Light colors into a single color and 3 intensities, changed sf::Text and sf::Sprite to use Triangles instead of Quads, added a few more helpful methods to sf::Shader and sf::Transform.
Merge remote-tracking branch 'official/master'