Use CMake As Build System

[jnhyatt]

Visual Studio projects and solutions target a specific Windows SDK version and platform toolset. This means that someone using a different version of Visual Studio will either have to retarget the project (and then revert the changes before checking in to source control) or download the required platform toolset and Windows SDK. Both options have drawbacks and neither is particularly necessary. In addition, this code uses no platform-specific constructs or APIs, so cross-platform capability is trivial.

I replaced the Visual Studio project files in this repository (not submodules) with CMake build files, made to closely match those in msdfgen's repo. In doing so, I noticed that you already have both Visual Studio and CMake build files, and I can modify the pull request to mirror this functionality if you'd prefer.

The top-level project adds msdfgen as a subdirectory and then builds and links against it. No additional setup is required. .gitignore has been modified to reflect the lack of top-level Visual Studio project files. I've successfully built this using Visual Studio 16 2019 (compiler version 16.6.2) on Windows and GCC 7.5.0 on Ubuntu WSL. On Linux systems where FreeType is already installed, it is detected automatically by CMake. On Windows, I found it necessary to manually specify the directory where FreeType is located.

Thanks for reviewing this! Let me know if there are questions I can answer or changes you'd like me to make.

[jnhyatt]

@Chlumsky I'd like to help contribute to this project, but if this is unwelcome, I will also be happy to stop opening issues and pull requests. I would, however, appreciate some communication if that's the case.

[Chlumsky]

Yes, deleting my project files is unwelcome. I have fulfilled all your other requests.

[jnhyatt]

Thanks for the info!