- generalized object caching and added new object caching class
- added object caching wherever kelondroTree was used
- added object caching also to usage of kelondroFlex
- added object buffering (a write cache) to NURLs
- added many assert statements; fixed bugs here and there
- added missing close methods to latest added classes
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@2858 6c8d7289-2bf4-0310-a012-ef5d649a1542
