AVALANCHE: Add thumbnail support and version tracking to the saving/loading system. Repair Trip::trippancy_link().
ZVISION: Handle rlf frame transitions internally

Animations use incremental frame changes. That is, only a few frames
are complete (I-frames), the rest are just the pixels that change between the current
frame and both the previous frame and the next frame (B-frames). See
https://en.wikipedia.org/wiki/Video_compression_picture_types
ZVISION: Remove superfluous file
ZVISION: Add animation.o and rlf_animation.o to module.mk
ZVISION: Add TODO's of what is left for the engine to be complete
ZVISION: Add a destructor to Puzzle
ZVISION: Store the Puzzles in _activePuzzles and _globalPuzzles on the heap

This allows List::push_back() to not cause a data copy
ZVISION: Add TODO to subtitles
ZVISION: Delete Puzzles from heap before clearing _activePuzzles
ZVISION: Initialize Puzzle::key and Puzzle::flags

Some Puzzles don't have flags, which caused it to never be initialized
ZVISION: Remove static Control::parsePushToggleControl

The code was moved to the class PushToggleControl
ZVISION: Implement streaming support for RlfAnimations
AVALANCHE: Rename Gyro::reloaded to Gyro::isLoaded. Repair a bug in the original engine regarding timing of animations/scrolls/etc. when loading a savegame using this variable.
AVALANCHE: Implement opening of doors. Rethink a bit the graphics and the timer system to do so.
AVALANCHE: Rename special() to openBox() in Acci, implement it.
AVALANCHE: Upgrade Lucerna::enterroom(). Add r__yourhall to roomnums.h, handle it's cases in Lucerna:enterroom() and Trip::open_the_door(). Remove unnecessary typecasts in Celer::pics_link(), upgrade Celer::show_one(). Introduce Graphics::refreshBackground(), use it where needed.
AVALANCHE: Repair Acci::do_that(), Gyro::getname(), Lucerna::find_people(), triptype::walkto().
AVALANCHE: Upgrade Trip::apped(). Update rest of the code to call it and the previously upgraded Celer::show_one() properly.
AVALANCHE: Upgrade Trip::infield(), update the rest of the code accordingly. Repair Trip::neardoor(). Introduce Parser::handleFunctionKey(), partially implement it. Implement Gyro::f5_does(). Implement missing part of Lucerna::enterroom().
ZVISION: Make ZVision::_workingWindow and ZVision::_pixelFormat public