Arpu

1.add .gitignore & remove *.swp
2.def extra_files() to return ['/data/migo/athena/lib']
3.tested ok, ex:
python arpu.py Arpu2 --use-hadoop --source="data/small_data_prepare.src" --temp="luigi_arpu_small_1" --destination="luigi_arpu_small_2"