Setting include_toc is ignored.

[moigagoo]

Config value include_toc is not checked anywhere in the theme despite being defined in config.html (https://github.com/iamale/mkdocs-alabaster/blob/master/mkdocs_alabaster/config.html#L7) and mkdocs.yml (https://github.com/iamale/mkdocs-alabaster/blob/master/mkdocs.yml#L16; BTW shouldn't it be true?).

Its value is therefore ignored, and ToC is shown nonetheless.