New display creation signatures. Fullscreen support. Removed icon class. - Added new Display::Options struct that wraps together display creation parameters. New Display::create() with an Options object as argument. - Added support for specifying fullscreen mode, through the fullscreen flag. - Removed Icon class. Now Display::setIcon expects a string with a image filename. The Icon class was not necessary given its limited capabilities and the previous Display::setIcon leaked when exchanging icon instances. - Removed resizeable flag argument from Display::create() (non-Options version). Now it can only be specified by the Options argument's version of Display::create(). - Window position can be specified by Display::Options, including centered window. - Display::setIcon is marked as unimplemented in the SDL 1.2 adapter as the previous implementation simply didn't worked, given SDL 1.2 limitations. Setting an icon is still possible when creating the display for the first time.