test case generator (more features)

[skhuang]

1. more efficient input generation (random selection between input value range, check the input constraint. 過程可能會一直找不到符合的輸入值)。
2. 依照難度的輸入，更多筆數的輸入資料(根據 size, < 5k < 10k ), download link for large input and output files.
3. fault localization with diff options (用顏色區別不同的輸出)
4. input specification -aware fault localization (了解輸入格式的除錯功能)

[skhuang]

1. input validation (validator)
2. user contributed input and output from AC programs