Fix hidden options window in screenshot mode

Opening the options window with Escape while in screenshot mode would
not draw the window, but would steal focus and deadlock the game's input

This is resolved by simply adding a path to draw modals even if
the UI is in "screenshot only" mode, as the escape menu should be
irrespective of that mode.

data/pigui/libs/modal-win.lua

@@ -74,4 +74,8 @@ ui.registerModule('mainMenu', function()
 	drawModals(1)
 end)
 
+ui.registerModule('modal', function()
+	drawModals(1)
+end)
+
 return ModalWindow

data/pigui/views/game.lua

@@ -297,6 +297,8 @@ ui.registerHandler('game', function(delta_t)
 				end
 			end
 		end
+
+		callModules('modal')
 end)
 
 return gameView

data/pigui/views/mainmenu.lua

@@ -252,6 +252,7 @@ local function showMainMenu()
 	end)
 
 	callModules('mainMenu')
+	callModules('modal')
 end -- showMainMenu
 
 ui.registerHandler('mainMenu',function(delta)