cmake-format v0.6.12

This release includes mostly internal housekeeping. The code organization was overhauled to better represent the division between
different components.The cmake_format package has been replaced by cmakelang, with`format` now a subpackage. All the first class tools are now subpackages of cmakelang. For now, I'll leave the github repository at cmake_format but there's a good chance I'll move it to cmakelang in the future. Big refactors like this have a tendency to expose gaps in coverage so please report any breakages you observe.

In addition, the configuration now includes options for using tab characters in listfiles (though, I'm not sure who in the right mind would choose to do so). If enabled, the formatter will translate indentations from spaces to tabs,and the linter will enforce a consistent tab policy.

This release also includes a couple of minor bug fixes. See the release notes for more details.