STUDIO-2859
Add a "Recently modified diagrams..." sub-menu within the "Diagram" menu

Conflicts:
	bundles/plugins/org.bonitasoft.studio.application/messages.properties
	bundles/plugins/org.bonitasoft.studio.application/plugin.properties
	bundles/plugins/org.bonitasoft.studio.application/src/org/bonitasoft/studio/application/i18n/Messages.java