Replace default pikaday date (1st of January, year 0) with undefined
Construct date field with empty content when backend returns undefined date
Add missing semicolons
Merge pull request #89 from finnishtransportagency/improve_asset_creation

Improve asset creation
Merge branch 'master' of https://github.com/finnishtransportagency/digiroad2 into improve_asset_creation
Updated submodule after merge