Crafting menu can be accessed even in the dark. [CR]

But the actual crafting can't be done if it's too dark to see.

In the latest versions of CDDA, I got frustrated by the "You can't see to craft!" message when trying to access the crafting menu while my character was in the dark. Sometimes I wanted to check what I need to make a certain item. I think the crafting menu should be available even if it's too dark to actually craft.

My reasoning behind this: The crafting menu is a part of the character's knowledge/memory. In real life I can think about what I need to make a pizza even if I turn off all the lights in the middle of the night. I'm also able to remember if I have flour, cheese, tomato sauce etc. But I wouldn't be able to actually make the pizza in total darkness. In the same manner my character should be able to think about stuff he knows how to make, and I guess he'd also have a general memory of what stuff/ingredients he has available.

Makes sense, no?

Question: should the "You can't see to craft" message be a normal message, or a popup? The popup is a bit more visible, but can be slightly more annoying. Is there a policy/guide to what should be a message and what should be a popup?

As you can probably tell, this commit adds the somewhat awkwardly named method game::crafting_can_see which returns true if you can see, false if not. (I just moved the vision code that was in crafting_allowed() into its own method.) This is then used to check if you can see to craft after you've selected a recipe.

It would also be nice if someone more familiar with the code could comment on this commit! There might be a better way of accomplishing what I've done here?