Template object parsing

[jpeletier]

Fixes https://github.com/SSBMTonberry/tileson/issues/100

This PR implements parsing of referenced template map objects within map files.

Tiled allows the concept of reusable objects or "templates" that can be instantiated into a map. To that effect, Tiled stores in a template file a JSON representing the object's base properties. When these template objects are instantiated, the map file only keeps a reference to the source JSON template file, plus any overriden properties.

When parsing a Tiled map's map objects, Tileson would only report the overriden properties, but not the object template's base properties.

This PR fixes that by parsing template files and returning a map object where all the base properties have been merged with the instance's properties the way that Tiled shows in its UI.

[SSBMTonberry]

@jpeletier: I'll have a detailed look into your PR and a proper review tomorrow, but thank you very much for your work😄 I've skimmed through the code tho, and can at least say you've done a nice effort to solve the problem in a clean way, for sure!

[jpeletier]

@SSBMTonberry Thank you for your comments. Awaiting your review to see what changes are needed. I tried to do my best to place things where I thought made sense, but there will be for sure better places or approaches. I have this already working in our internal fork with our application and is running fine. Cheers!

[SSBMTonberry]

@jpeletier: Sorry for the delay. I didn't get time to do the review yesterday :disappointed:

I am very satisfied with your solution to the problem! The code is clean, and you have solved the problem in a nice manner. Only thing missing is to run the script to generate the tileson.hpp and tileson_min.hpp single header files. To do this you simply go into the tools folder and run one of these scripts in a terminal / cmd promt:

• On Windows: amalgamate_script.bat
• On Linux: amalgamate_script.sh
• On Mac: amalgamate_osx.sh

If you could do that, it would be nice :slightly_smiling_face:

Will approve this anyway, though, but I'd have to generate the files myself if you don't do it :stuck_out_tongue_winking_eye:

Ideally the generator for these files should be in a more automated process, but as it stands it's not. I might create an issue on that to make it into the next minor version of Tileson.

Thank you very much for your contribution! Much appreciated! :pray:

[jpeletier]

@SSBMTonberry done!

[SSBMTonberry]

@jpeletier: Perfect! :muscle: