Fix scifio-bf-compat bundle version and required bundles

'.' instead of ',' caused problems in generated MANIFEST.MF. Also fixed
version of scifio-bf-compat dependency not managed by pom.imagej and
removed obsolete imglib2-meta dependency exclusion.
Remove execution requirement of manifest

Was in an incorrect location, in which it had no effect. Since this
does not seem to be required, it will *not* appear somewhere else instead.