ZZT for the NES: an unofficial NES port of ZZT 3.2

This port is a modified version of The Reconstruction of ZZT
(https://github.com/asiekierka/reconstruction-of-zzt) and is distributed under that
project's license, below. No copyright is claimed in the changes and additions made
for the port.

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Copyright (c) 2020 Adrian Siekierka

Based on a reconstruction of code from ZZT,
Copyright 1991 Epic MegaGames, used with permission.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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Other parts:

- data/cga8x8.bin, and the 4x8 font tools/mkfont4.py makes from it: the IBM CGA
  font from The Ultimate Oldschool PC Font Pack by VileR (https://int10h.org/),
  CC BY-SA 4.0 (data/FONT-LICENSE.txt). The fonts in the ROM are adaptations of
  it under the same license.
- data/help/: help texts adapted from The Reconstruction of ZZT's (above).
- ZZT's worlds are not included. ZZT, Town of ZZT (TOWN.ZZT) and the ZZT demo
  world (DEMO.ZZT) are (c) 1991 Epic MegaGames; README.md says where to get them
  to build the ROM.

This is an unofficial port, not affiliated with or endorsed by Epic Games.
