== General ==
* make a clean implementation of double-buffering, with centralized updateScreen(). This would significantly deviate from the original engine, but may be the only way to effectively implement hardware-based effects (like half-brite). Other versions of the engine will surely benefit from a clean approach, too.
* merge input loops: make one input routine for menu, one for dialogue and one for _c_endIntro (possibly merge it with menu). It would be probably needed as part of the new double-buffering implementation. Should be worthy to investigate if it can be made '''before'''.