Pytiled-parser

Exposed tileset parsing more directly. This was possible by accessing the largely internal interfaces within pytiled_parser already, but this provides the same interface for parsing Tilesets as we have for parsing maps. You can parse a tileset by simply passing the filepath to `pytiled_parser.parse_tileset(file)` where `file` is a `pathlib.Path` object.

We have also removed some unnecessary `Optional` typing from some attributes. This does technically mean there are changes to the API, but they shouldn't really effect anything. The `pytiled_parser.Tile.width` and `pytiled_parser.Tile.height` attributes will now default to 0 if they are not set. Under normal circumstances there does not exist a scenario where they can not be set, the only use case that would cause this to happen would be if the map/tileset file does not follow the Tiled specification. The `pytiled_parser.TiledMap.map_file` attribute is also no longer optional, but does not have a default. This does mean if you were using the constructor for this class directly instead of the parsing functions, you would need to fix your usage of it, however it is extremely unlikely that anyone is doing that.

Switched to `pyproject.toml` for project setup. This should have no impact on users unless you are on a very old version of pip. If pip fails to install pytiled-parser, please try updating pip.

Fixed a bug in the TMX format where overriding or adding extra elements/attributes to object templates would not be applied. Only the id and the x, y position would be used. Now any overriden values(including properties) should be applied to the template. This bug did not exist in the JSON format, however there was no test coverage for this scenario in either format, that has since been added.

Added official support for Python 3.11. No changes were actually made to do this, and most all previous versions of pytiled-parser should work fine with 3.11. We are just now including 3.11 in the matrix of Python versions we run tests for.

Improved compatibility for pre-1.0 Tiled JSON formats([65](https://github.com/pythonarcade/pytiled_parser/pull/65)). This does not necessarily mean we guarantee support with older versions of Tiled, support for older versions will be on a best effort approach.

Added support for the following features from Tiled which were added in either Tiled 1.8 or 1.9. If you would like some more info on some of these items, please refer to the [release notes](https://www.mapeditor.org/news) from Tiled for those versions:

- **Tilesets**

- `Tileset.tile_render_size` has been added, which reflects the `tilerendersize` attribute from Tiled. This is a string value which can be either "tile" or "grid". This is used to determine the size the tile will render at. This defaults to `tile` and is the only behavior prior to Tiled 1.9, meaning it will use the size specified by the Tile. If this is set to `grid` it will scale the tiles to the size defined the grid in the map.
- `Tileset.fill_mode` has been added, which reflects the `fillmode` attribute from Tiled. This is a string value which can be either "stretch" or "preserve-aspect-ratio". This is used to define how the scaling will be done when a tile is not rendered at it's native size(Like when using the `grid` option for `tilerendersize`).
- The `Tile` class has four new attributes: `x`, `y`, `width`, and `height`. By default, `x` and `y` will be zero, and `width` and `height` will be the same as `image_width` and `image_height`. These values are only able to changed for tiles which use an individual image rather than a single image file for the whole tileset. These values are used to define a sub-rectangle of the image which the Tile should be loaded as. These are all separate attributes rather than using the `OrderedPair` and `Size` classes as this is somewhat of a developing feature in Tiled in an effort to support sprite atlasses, and so for now we are going to just stick as closely to the underlying format as possible for it, to make future changes easier.

- **Layers**

- Added `repeat_x` and `repeat_y` attributes. These are derived from the `repeatx` and `repeaty` attributes in Tiled. These are boolean values which are used to determine if a layer should be repeated on a given axis when drawn. As of writing in Tiled these values can only be applied to Image layers, however it is possible other types will support this in the future. To prepare for this, these values are available to all layer types in pytiled_parser, and they will default to `False`.

- **Maps**

- Added `parallax_origin` attribute. This is an `OrderedPair` object which is derived from the `parallaxoriginx` and `parallaxoriginy` attributes in Tiled. This is used to define a map wide origin point that layers which have parallax scrolling will use.

This version does not make any changes to the library. The project has moved to using Github Actions to publishing the distribution to PyPI. We have made this release to fully test the system and ensure it is functional for future releases.

This version contains just one bug fix. Previously if a map or other object in the TMX format contained a [Class property](https://doc.mapeditor.org/en/stable/manual/custom-properties/#custom-types) which was added in Tiled 1.8, then pytiled-parser would crash.

Classes are not a supported feature in pytiled-parser yet, however the existence of them isn't intended to break the rest of the supported featureset. This fix makes the rest of the map still be able to be successfully parsed and used if one of these exists in it.

See [60](https://github.com/pythonarcade/pytiled_parser/pull/60) for more info on this bug. Thanks to [laqieer](https://github.com/laqieer) for this PR.