Overhaul everything

- Add all C header files from ncurses 6.3.

- Re-translate from scratch those header files which have been
  translated.

  The combination of major ABI changes in ncurses 6, plus a history of
  people finding bugs in the bindings indicating their inaccuracy,
  makes for a good argument to take a scorched earth approach and
  perform a fresh translation of the headers, automating it as much as
  possible, and deviating from the C code as little as possible to aid
  in future maintenance efforts.

- Restructure the package layout to be consistent with other Deimos
  projects.

  Note that, being an implementation of a POSIX standard, ncurses
  places its header files (such as "form.h") directly under
  /usr/include. Therefore, the corresponding D module is at
  "deimos.form".

- Switch to ".di" files. Ensure no object code need to be generated.

  This simplifies linking (e.g. building a program using ncurses
  without dub / rdmd / dmd -i), and is closer in spirit to C header
  files.

- Add "pragma(inline, true)" to functions implementing C macros, to
  guarantee that compilers don't assume object code for them exists
  somewhere.

- Convert all dub.json files to SDLang.

  (SDLang is the winner format as it allows documenting decisions made
  in writing the build description.)

- Use "path" directive in examples' dub.sdl files to make them use the
  current checkout instead of what's committed on the master branch.

- Delete ISSUES as these are better tracked using an issue tracking
  system (https://github.com/D-Programming-Deimos/ncurses/issues).

- Delete AUTHORS as this is better tracked by the Git history. dub.sdl
  has a list as well.

- Delete the non-standard "nclear" alias. (Presumably disambiguator
  for object.clear before that was removed.)

Author: CyberShadow