If Window Image Cache Lifespan is 0, Don't Cache

[ShlomoCode]

If Window Image Cache Lifespan is set to 0 (ie a completely fresh image every time), there is no need to save image cache, thus saving the user RAM.
@ejbills

[ShlomoCode]

Dependent on #238

[stevehoek]

I have my cache setting to the lowest non-zero setting and it still shows old previews. How can you force it to refresh dock preview without restarting DockDoor? I've activated the window, minimized and restored, etc. and it still shows an old preview image

[ShlomoCode]

@stevehoek This sounds like an unrelated bug, please open a new bug issue and fill in all the required information

[ejbills]

I have my cache setting to the lowest non-zero setting and it still shows old previews. How can you force it to refresh dock preview without restarting DockDoor? I've activated the window, minimized and restored, etc. and it still shows an old preview image

Latest update should fix.