support NOTed filtering
support filter-<key>__ne instead
add UI support w/ onoffswitch
make 'content' clickable as toggle for negation
revise and add test cases for negation filtering
multiple pinned keyword filters are not colored correctly
fix bug: pinned negated keyword filters not work
support PrefixIDFilter
added a test case for PrefixIDFilter
fix bug: no warning message when switching state on pinned keyword filters