Make the HelpFrame re-usable for other help texts

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Merge remote-tracking branch 'origin/importer' into mamut
TextOverlayAnimator: make its position reusable

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
git ignore Mac OS' .DS_Store
Merge branch 'mamut'

Conflicts:
	src/main/java/viewer/HelpFrame.java