Common interface for <LLEntry> iterators
[new index structure] merge master
[new index structure] Adjusted BTreeIndex to new iterator interface.
[new-index-structure] Initialized root of BTree during the constructor call.
Merge branch 'new-index-structure' into prefix-sharing

Conflicts:
	src/org/zoodb/internal/server/index/BTreeIndex.java
	src/org/zoodb/internal/server/index/btree/BTree.java
[prefix-sharing] Manual merge with new-index-structure.