Major: 0.0.16

New Features:
1. Add ID3v2 track number read.
2. File size now sort by real size.
3. Add artist view widget.
4. Use sort proxy model instead of original model.
5. Remove Purchase Date and Release Data column.

Updates:
1. Change date display to new format.
2. Change header text to left alignment.

Bug Fixed:
1. Fixed the track number might be minus bug.