spawn_level attribute
Change indentation to tabs.
Allow dropping stash items directly and fix stacked items pickup bug
Don't drop stash items when dragging into a full inventory

Fixes #748
Check quantity in ItemStorage::full()
Fix picking up loot stacks from the ground with a full inventory
Restore old stash full checking

When trying to move items to a full stash from the inventory, we don't
have to worry about splitting the stack.
Merge pull request #108 from clintbellanger/master

merge from master
Merge pull request #107 from stefanbeller/771

Change indentation to tabs.
Merge pull request #111 from clintbellanger/master

merge from master
npc requires_status and requires_not
update comments
Merge pull request #114 from clintbellanger/master

merge from master
visible_requires_status for menu powers
Replace requires_not by requires_not_status to be more consistent in style

Closes #407
Use a list of states for the requires[_not]_status in NPC

This is consistent with the quest events, which can have a list of
states as well. Maybe we should think about having that code only once
in a generic fashion.
Merge pull request #118 from stefanbeller/proposal772

NPC requires_status consistent to quest requires_status
Merge pull request #749 from dorkster/menu_stash

Improvments to stash interaction
Adapt to coding style
Convert Power_Menu_Cell::visible_requires_[status,not] to lists