Zhihan/debugging mode

[ScarletGuo]

Evaluation

• added try exception around precision/recall computing
• returned list of evaluation stats for the purpose of auto recording in batch runs

  Data Loading

• added .lower() to column 'value' when loading clean dataset in order to match the normalization process in loading dirty datasets
• fixed formatting error in table.py's constructor

  Repair

• stored the weights of featurizers after training in repair model
• return the above in the format of string
• optionally print the string above with a newly added flag --printfw