BF download

Point to latest B-F released version.
To test:
 * Add insight-ij to ImageJ plugins folder
 * Remove bf-package or loci_tools from ImageJ plugins folder
 * Start ImageJ, Go to the Plugin menu and select "Connect to OMERO"
 * A dialog will pop up indicating to download BF. Click on the link. The Link should redirect you to http://downloads.openmicroscopy.org/bio-formats/5.0.0-rc1/