remove pe_status from enumerations.
remove pe_status.
remove unneeded tests.
remove pe_status steps.
remove steps not needed any more.
changelog.
noneSelection and noneElement in translation.
Adds changelog entry
fix bug when time_types is an empty array.

I do not know why it is this way, but this makes
the timelines.js code more robust and fixes the bug.
Merge pull request #539 from opf/fix/no_data_to_display
Merge pull request #538 from opf/fix/none_translation
PlanningElementStatus no more.
Merge remote-tracking branches 'opf/feature/rails3' and 'opf/fix/remove_pe_status_enumeration' into fix/timelines-api-migration

Conflicts:
	doc/CHANGELOG.md