Prevent the color extension from auto-loading

[pkra]

Fixes #175

[dpvc]

I'm wondering if a test that checks the result of something like \color{red}{x}x might be worth adding, since with the original autoload-all, this would make both x's red, while with the modification, it should only make the first one red.

[pkra]

I'm wondering if a test that checks the result of something like \color{red}{x}x might be worth adding,

Will do.

[pkra]

New test added.

[pkra]

ping @dpvc

[pkra]

Thanks!