nessDB v3.0

Preface:

a) Every ness-block size is 4MB
b) Every ness-block contains 16 ness-nodes(one is top-buffer), each ness-node size is 256KB(4MB/16)

Processing:

1) Insert:

	a) If top-buffer is not full: insert to end & compressed the buffer,write to disk 
	b) If top-buffer is full: flush items among 15 ness-nodes
	c) If someone ness-Node is full: flush items to child ness-block
2) Query
	a) Find in the top-buffer
	b) If not found, then goto ness-node
	c) If not found, then goto child ness-block,and go on