BS-2071

Add migration of returnType and referenced elements of Connector of 5.x to Operation in 6.x. + add test

Conflicts:
	bundles/plugins/org.bonitasoft.studio.importer.bar/src/org/bonitasoft/studio/importer/bar/custom/migration/connector/Connector5Descriptor.java
BS-2287

Changed activeWhen by enableWhen property in handlers for Undo/Redo command in the Edit menu
BS-2287

Remove extra activeWhen balise
BS-6855
Missing text already existed in an other plugin.
Merge branch 'master' into 'MasterBugFixing'
Merge branch 'MasterBugFixing' into 'master'