Update version numbers to 4.4.8
Fix link to ImgOpener.java with the move of imglib2/ to io/
Merge pull request #498 from sbesson/imglib2_link

Fix link to ImgOpener.java with the move of imglib2/ to io/
Merge pull request #497 from joshmoore/4.4.8-version

Update version numbers to 4.4.8