Closes #75: Fix multiuser double-middle-click

[alex-f-k]

Fix #75: Subscribe to SessionDidResignActiveNotification and SessionDidBecomeActive to kill and resurrect touch callbacks

⚠️ This is my first try at Obj-C, beware ⚠️

Steps to reproduce

• Switch to another user (lock screen doesn't cause the app to pause)
• In Firefox with enabled General -> Browsing -> Use autoscrolling use middle click
• Even if second user doesn't have the app running, it would click at the coordinates where the mouse was before the first user logged out

Hopefully with this fix it won't do that anymore :)

To be aware

• Tested with 2 users both running the app from /Applications, not /Users/<user>/Applications. Seems to work fine, but console log is a bit sussy:
  Multiple `Display reconfigured` calls right before login that schedule a restart AFTER the app has just got mouse listeners from the `BecomeActiveNotification`

default 14:06:34.762468+0000    MiddleClick HIDAnalytics Set Value Send event com.apple.iokituser.hid.iohidpostevent
default 14:06:34.762535+0000    MiddleClick HIDAnalytics Unregister Send event com.apple.iokituser.hid.iohidpostevent
default 14:07:07.024424+0000    MiddleClick Display reconfigured, restarting...
default 14:07:07.024468+0000    MiddleClick Display reconfigured, restarting...
default 14:07:07.157756+0000    MiddleClick User logged out, stopping...
default 14:07:07.157826+0000    MiddleClick Stopping unstable listeners...
default 14:07:09.025388+0000    MiddleClick User is logged out, abort restart...
default 14:07:09.204876+0000    MiddleClick Restarting app functionality...
default 14:07:09.204957+0000    MiddleClick Stopping unstable listeners...
default 14:07:09.206677+0000    MiddleClick Starting unstable listeners...
default 14:07:20.765225+0000    MiddleClick Display reconfigured, restarting...
default 14:07:20.765295+0000    MiddleClick Display reconfigured, restarting...
default 14:07:20.922754+0000    MiddleClick Display reconfigured, restarting...
default 14:07:20.922790+0000    MiddleClick Display reconfigured, restarting...
default 14:07:21.062414+0000    MiddleClick User logged back in, restarting...
default 14:07:21.062483+0000    MiddleClick Starting unstable listeners...
default 14:07:22.766397+0000    MiddleClick User is logged out, abort restart...
default 14:07:22.923851+0000    MiddleClick Restarting app functionality...
default 14:07:22.924016+0000    MiddleClick Stopping unstable listeners...
default 14:07:22.955471+0000    MiddleClick Starting unstable listeners...

• May-or-may-not (I have no idea) cause mac to basically stop responding

I was testing, second user was logging in (initiated the switch with the fingerprint scanner) and it just didn't log in the second profile. Only showed lock screen with the spinning symbol (not beachball) instead of password field

Additionally I tried clicking on the first user again and typed the password - same thing, just a spinner and no progress

Maybe it is caused by some race condition from the previous log and I happened to switch too fast between them, but I really have no idea