1. do not print handleNewSpill log in MapTaskImpl;
2. do not recompute when a task fails;
3. in MapOutputBuffer, fix end of sortAndSpill to end of current split;
4. add combiner cache related counter
5. fix readEnoughToSpill bug, use len of current spill
6. change hao.spill.interval.minutes to seconds
7. add haoQuery and buggyWordcount