complete task1 except proper test case
modify TestTask2_1.java
Merge branch 'task2' of https://github.com/buzouxun/SimpleDB_2.10 into task2
modify TestTask2_1 from sh to eh
Merge branch 'task2' of https://github.com/buzouxun/SimpleDB_2.10 into task2
modify test task by adding comments in next()
Merge branch 'task2' of https://github.com/buzouxun/SimpleDB_2.10 into task2
add hash in secondhashindex