validate numeric and date options in timelines.
changelog.
also except nil values for date&numeric. (=empty)
There is no 31st of february.
Merge remote-tracking branch 'opf/feature/rails3' into feature/timelines_option_validations

Conflicts:
	doc/CHANGELOG.md
Merge pull request #662 from opf/feature/timelines_option_validations

timelines option validations