Disable to move WBS-Project-Element to node that can't get new child: refs #451 #422
lib/effort_breakdown.rb: refs #422
Merge remote-tracking branch 'origin/dev' into dev

Conflicts:
	app/controllers/wbs_project_elements_controller.rb
	app/helpers/wbs_activity_elements_helper.rb
	app/models/wbs_project_element.rb