Show the game's green arrow outside the battlefield

NewPlanned for 0.2.0

Over the game’s menus and dialogs, and wherever no battlefield pointer is up, the pointer is now the game’s green arrow, enlarged like the battlefield pointers. It was a black and white arrow at a fixed size. The arrow is cursor.png in the ui directory, so a mod can replace it. SystemCursor=yes, or the switch on the display options screen, shows the Windows pointer there instead.

Affected entities

AddedSystemCursor
ChangedCursorScale
Changedui-files

Credit: ZivDero