move all sdl source files in a proper directory
remove hackish code to get a window up, now it should be quite clean
#import <UIKit/UIKit.h>
const char* get_documents_path() {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex: 0];
return [documentsDirectory UTF8String];
}