Increase progress count only when the next file is read (and not the next series).
Re-initialise reader in ScifioImgSource when its metadata has been set to null.

The metadata of a reader is set to null after an image (one series) has been read (the ImgOpener closes the reader).
Bug 5158. Fixed

Use Cross Platform Look&Feel for the JFileChooser instead of the
default one.
Merge branch 'master' into imgsaver