this is a migration step to support a new method to store the web index, which will also based on the same data structure. made also a lot of refactoring for a better structuring of the BLOBHeap class.
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@5430 6c8d7289-2bf4-0310-a012-ef5d649a1542