To use LevelDB, follow these steps:

1) At the top of the directory tree, type:
	make -C src/cpp/leveldb libleveldb.a

2) In the SConstruct file, change
	LevelDB = bool(0)
to
	LevelDB = bool(1)

3) Compile with 'scons'.

There is no import or export method, so your server will have to refetch
all nodes. For simplicity, we recommend clearing your entire 'db' directory.
LevelDB will store the hash nodes in a 'db/hashnode' directory.