removes scenarios and alternate dates
fix translation missing
updates changelog
Merge branch 'feature/rails3' into feature/remove_alternate_dates_and_scenarios

Conflicts:
	doc/CHANGELOG.md

[skip ci]
Merge pull request #369 from opf/feature/remove_alternate_dates_and_scenarios
Merge branch 'feature/rails3' into feature/rails3_move_pe_controller_to_api_v2

Conflicts:
	app/controllers/planning_elements_controller.rb
	app/models/planning_element.rb
	app/views/planning_elements/_form.html.erb
	app/views/planning_elements/_planning_element.html.erb
	doc/CHANGELOG.md