Style variation default dark 1.0

Sets the style variation default to dark.

Questions and answers:

Q: When a visitor (not logged in) views my site, will they see the dark style variation?
A: Yes.

Q: When a user registers will the style variation remain dark?
A: Yes.

Q: When a visitor (not logged in) views the site, can they change to the light style variation?
A: Yes.

Q: Can logged in users change the style variation and will their desired variation be saved?
A: Yes. Their desired style variation is saved in the database so it will always show their desired style variation.