Fix the bug that the program will be crash if the URLConnection Download data is nil.
Merge pull request #6 from whmsysu/develop

Fix the bug that the program will be crash if the data parament is nil
update Contributors
A naive feature that when download finish, it will pop out a notification window.
add a type casting to avoid warning of CC_MD5
Add the new feature that pop out notification if all the download task finish.
Merge pull request #9 from whmsysu/AddNotification

Add a new feature that pop out a notification if all download tasks finished
- update develop version to v0.5.3.
- fix notification center  problem, that videos mix no subtitle video will cause no notification.
Rearrange some logic structure
Fix the bug that if one file do not have sub it will not post notification.
Try to remove the nonatomic property
Merge pull request #10 from whmsysu/FixTheNoSubBug

Fix the no sub bug
small notification change
Delete some extra post notification code
Add paste directory surpport
Add a new feature that remove item button can remove multiple selected item now.
Add a new feature that users can press header to sort the corresponding column
Fix the size sorting bug
Giving some comments for functions used by the sorting feature.
Add App Icons according to their require size