update CHANGES

change NOTIF_UPDATE to trigger an update notification

add idle-timer.min.js to MANIFEST

add localStorage.TRACK to enable tracking in dev env

update CHANGES.md

update CHANGES.md

update CHANGES.md

mixpanel: use the old prepareProps on button click

mixpanel: set superprops when installing

makes sure that they are sent before going to options

mixpanel: make options usage data super properties

- wilting threshold as raw value
- topics as true/false as previously