version qingRS-0.0.3
add test: QingDataModelTest.java
get information like below
	user warning(0)
	item warning(743)
	Preference=(1.0, 5.0)
	usersNum=943, userMean=106.04453870625663, userVar=100.87821227051644
	itemsNum=1682, itemsMean=59.45303210463734, itemsVar=80.3599467406018