IndicatorManager.IconCache — The class caches icon objects in case they're reused shortly aftwerwards.
The icon cache caches icon objects in case they're reused shortly aftwerwards. This is necessary for some indicators like skype which rapidly switch between serveral icons. Without caching, the garbage collection would never be able to handle the amount of new icon data. If the lifetime of an icon is over, the cache will destroy the icon. (!) The presence of an inUse property set to true on the icon will extend the lifetime.
how to use: see IconCache.add, IconCache.get