* Add trace filter by category
- fixes#39
- fixes#57
* Fix combination of filter types
* Refactor filter
- use idiom 'seq' to check for empty sequences
* Make small refactorings in filter code
* Refactor toggle-category-fn to use set operations
* Restyle table for readability
* Make op text colours accessible AA standard
* Table to full panel width
* Separate traces with stripes in classnames
* Trace detail arrows brighten on focus state
* Show print icon when hovering on trace detail
* Clean filter inputs and accessibility focus
* Make filtering state more obvious
* Click trace filtering count to reset filters
* Remove redundant buttons