Fixes around ScriptEditor script list
Created by: pouleyKetchoupp
- Fixed "Previous Script" shortcut not working (CTRL+SHIFT+<)
- Fixed crash (integer division by zero) when using previous/next script shortcut with no script open
- Fixed error when dropping a script file with no script open
ERROR: ItemList::get_item_metadata: Index p_idx=-1 out of size (items.size()=0)
At: scene\gui\item_list.cpp:257