Compressed student ID in both CSV and the heap.

1. Moved the random CSV generator to name_gen/run.py to MakeStudentCSV.py
2. MakeStudentCSV.py now generate CSV with student ID compressed by default,
   instead of string format like 'DB123456'. See './MakeStudentCSV.py -h'
   for option to generate normal student ID.
3. Renamed TestCSVHeapConvert.cpp to MakeHeap.cpp -- It's not a test anymore.
4. A StudentID-compressed CSV file is attached. See StudentMini.csv. The
   executable sid_compress/sid_compress is used by MakeStudentCSV.py now.