uGet

Invalid date

1. Show only one notification in most case.
2. Fix: URL Sequence batch works very slow.
3. Fix: Program can't open downloaded files in external SD Card.
4. Fix: Program doesn't save data after queuing/deleting category/download.
5. Fix: Program will remove notification when device rotated.

Known bugs:
1. All downloaded folder in external SD Card must be reselected after device reboot.
2. If user change sorting type in Settings, it sort very slow.