Windows and MacOS installers (.msi / .dmg / App-XXX.zip / App-XXX.tar.gz) are missing filter plugins #476

The installers for Linux (.deb / App-XXX.tar.gz) contain filter plugins from the hdf5_plugins repository. These are missing from the Windows and MacOS installers. Either the intention is these should be bundled with HDFView or a user may have to install them separately, but this should be consistent among platforms.