[theme-reviewers] Note to theme reviewers about settings in themes

[Otto]

This is just a note about a rule that I think should be added to the
theme review process:

- Themes should not do anything to the database merely by virtue of
being activated.

By that, I mean that having a theme check for a setting, like
get_option or get_theme_mod and then calling set_option or
set_theme_mod to set it to some default is wrong.

Both get_option and get_theme_mod accept a second parameter of a
default setting. If I call get_option('whatever',123) and there is no
whatever option, then that will return 123.

Use the defaults properly. Don't set them just because they're not there.

-Otto