Handle null/undefined assignment, add non-inline list-item template support
Fix nested mapping issue
Fallback using MutationEvent if MutationObserver is unavailable
Fix list item data binding issue

- bind all direct children of list container
- fix incorrectly assigned dataRoot for list item
- add find binding by element and its parents in a binding scope
- add "bind" binding option, but this can be obsoleted in future
Add tests to cover list item default data binding
Add attribute update and update version to 2.1.0
change data-drive-attr- to accept template
Add defaultVal and initialVal for Scalar type
update build and add minor test cases