update to low-level-tests.js
update to low-level-tests.js

add tests for
 - keyboardPropagationMode
 - pointerPropagationMode
 - widgetTypes
 - interactionMode
 - errorCodes
 - policyAction
 -
 - eventKind
 - eventmodifiers
 - eventTypes
 - supressScrollbars

refine naming
 - overscrollMode terminology change

lxfschr/spaces-adapter,lxfschr/spaces-adapter