Make sure the Sirius integration is available with contextual explorer

Without those dependencies the Sirius integration might not be installed
and as such the user don't get any feedback when clicking in a Sirius
diagram.

org.eclipse.emf.ecoretools.explorer.contextual/META-INF/MANIFEST.MF

diff --git a/org.eclipse.emf.ecoretools.explorer.contextual/META-INF/MANIFEST.MF b/org.eclipse.emf.ecoretools.explorer.contextual/META-INF/MANIFEST.MF
index f3f0636..5df6c35 100644
--- a/org.eclipse.emf.ecoretools.explorer.contextual/META-INF/MANIFEST.MF
+++ b/org.eclipse.emf.ecoretools.explorer.contextual/META-INF/MANIFEST.MF
@@ -8,6 +8,8 @@
  org.eclipse.core.runtime,
  org.eclipse.amalgam.explorer.contextual.core,
  org.eclipse.amalgam.explorer.contextual.ui,
+ org.eclipse.amalgam.explorer.contextual.sirius,
+ org.eclipse.amalgam.explorer.contextual.sirius.ui,
  org.eclipse.emf.ecore.editor
 Bundle-ActivationPolicy: lazy
 Bundle-RequiredExecutionEnvironment: JavaSE-1.7