Rename vallu import to vallu export
Save old vallu exports to disk
Fix varible declaration in vallu export
Group adjacent bus stops as a stack
Fix root handling
Remove unused parameters
Hide bus stop grouping behind feature flag
Refactor
Merge pull request #269 from finnishtransportagency/grouping-assets

Grouping assets
updating pictures to operator manual
Revert "Merge pull request #269 from finnishtransportagency/grouping-assets"

This reverts commit b35eeaabacc6b6fb243e1dde554c4e97d0d123ab, reversing
changes made to b7d79f64d31745da16b97dc3b45748004e8a62e1.
Disable `Tallenna` and `Peruuta` if no changes
Use `selectedAsset.isDirty` instead of custom fn
Mark selected asset as dirty upon creation
Merge pull request #270 from finnishtransportagency/disable_form_buttons_when_state_not_dirty

Disable `Tallenna` and `Peruuta` if no changes
Refactoring asset layer wip
Simplified asset layer implementation (wip)
Direction arrow turning
Cleaned a lot of stuff from asset layer (wip)
Fix validity period change