Guideline update

[katajainen]

Please note that the community guidelines have been slightly revised:

The default content setting is now "suitable for everyone", with instructions to select an appropriate setting if posting anything NSFW, the reason being that - after some careful consideration -your mod and benevolent dictator came to the conclusion that a shipping community is not inherently mature content. (And that anyone who can use DW can also learn to mark their content appropriately.)