ToDo

1. Handle raw image files, see if https://github.com/sdcb/Sdcb.LibRaw can be used to handle the IO. One possible problem is probably extracting Exif properties from raw files.
2. More intuitive way of removing tags from an image. Can be done by adding a delete tag context menu drop down. Done in version 0.0.0.3.
3. Improved visualization of rate. Fill all stars from and below? Change color of filled star? Implemented filling of stars from 1 to given rate. Done in version 0.0.0.3.