test: split basis.dom.wrapper suite
basis.dom.wrapper: selection improvements, bug fixes and bb-value support for selected

- only instance of Selection could be a Node#selection
- Node#setSelection() now treat any non Selection instance value as
config for new Selection
- no more select/unselect events on init and destroy
- auto unlink Selection instance from nodes on instance destroy
- support bb-value for selected
- test suite and various bug fixes