Tcod

Added
- Added new algorithm `FOV_SYMMETRIC_SHADOWCAST` based off of the code
provided [here](https://www.albertford.com/shadowcasting/).

Changed
- `TCOD_map_compute_fov` and `TCOD_map_copy` now return error codes.

Added
- Tilesets can now be loaded from an in-memory PNG file or from raw data.
- The character mappings `TCOD_CHARMAP_CP437` and `TCOD_CHARMAP_TCOD` are now
public.
- Added `TCOD_rng_splitmix64_next`.
- Added the `TCOD_VERSIONNUM` and `TCOD_COMPILEDVERSION` macros.
- Added vectorized noise generator functions.

Changed
- Video driver status info has been added to SDL video driver errors.
- Console blits now ignore alpha compositing which would result in division by
zero.
- Image loading now returns an error code.
- Added window `x, y` coordinates when creating contexts.
- Added `argc` and `argv` to contexts so that they can optionally support CLI
commands.
- A struct is used to pass parameters for creating contexts.
- The OpenGL 2 renderer can now use `SDL_HINT_RENDER_SCALE_QUALITY` to
determine the tileset upscaling filter.
- Improved performance of the FOV_BASIC algorithm.
[77](https://github.com/libtcod/libtcod/issues/77)

Deprecated
- Deprecated the following macros:
`TCOD_HEXVERSION`, `TCOD_TECHVERSION`, and `TCOD_STRVERSIONNAME`.

Fixed
- `TCOD_console_is_key_pressed` should work even if libtcod events are ignored.
- Fixed images only saving as a red channel.
[75](https://github.com/libtcod/libtcod/pull/75)
- The `TCOD_RENDERER` and `TCOD_VSYNC` environment variables should work now.
- `FOV_PERMISSIVE` algorithms are now reentrant.

Changed
- CMake can now create packages.

Fixed
- `TCOD_console_init_root` and context initializing functions were not
returning error codes on failure.

Changed
- Print functions will no longer treat special glyphs as double wide.
- Library CMake files now support Vcpkg.

Fixed
- Fixed divide by zero when handing mouse input without a global context.

Fixed
- Fixed characters being dropped when color codes were used.

Fixed
- `FOV_DIAMOND` and `FOV_RESTRICTIVE` algorithms are now reentrant.
[48](https://github.com/libtcod/libtcod/pull/48)
- Heightmap functions will crash less often when given out-of-bounds parameters.
[13](https://github.com/libtcod/libtcod/issues/13)
[50](https://github.com/libtcod/libtcod/pull/50)
- The `TCOD_VSYNC` environment variable was being ignored.
- Malformed UTF-8 strings will no longer hang printing functions.