Add eventbus dependency, as it got seperated from scijava-common

Author: Gabriel Einsdorf

org.knime.knip.imagej2.core/META-INF/MANIFEST.MF

@@ -33,7 +33,8 @@ Require-Bundle: org.knime.workbench.repository;bundle-version="[3.0.0,4.0.0)",
  imagej-deprecated;bundle-version="0.1.0",
  scripting-javascript;bundle-version="0.4.1",
  org.knime.scijava.core;bundle-version="0.2.0",
- org.knime.knip.cellviewer;bundle-version="1.5.0"
+ org.knime.knip.cellviewer;bundle-version="1.5.0",
+ eventbus;bundle-version="1.4.0"
 Bundle-RequiredExecutionEnvironment: JavaSE-1.8
 Bundle-ClassPath: ij2-core.jar
 Bundle-ActivationPolicy: lazy