Fix last modified date when updating asset
Merge branch 'master' of github.com:finnishtransportagency/digiroad2 into fix_last_modified_date
Merge branch 'master' of github.com:finnishtransportagency/digiroad2 into fix_last_modified_date
Simplify api by removing separate functions for updating asset location and properties.

Fix tests and remove those that became obsolete.
Merge branch 'master' of github.com:finnishtransportagency/digiroad2 into fix_last_modified_date
Rename updater -> modifier
Use default value for property sequence
Remove Option from asset properties saving. Use empty sequence when properties are not changed.
Merge pull request #201 from finnishtransportagency/fix_last_modified_date

Fix last modified date