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

[artginzburg]

By the logs you sent, it looks like: displayReconfigurationCallBack() fires twice, both of the callbacks schedule a restart in 2 seconds, then the user log out fires, the app stops listeners, and when the 2 seconds pass — one of the restarts is aborted, while the other one fires. I might be wrong here. Then the same thing happens with 4 callbacks — 3 of them get discarded, and one makes it.

But it is sure that scheduleRestart invalidates any existing restart timer, so that 2 restarts can't happen at the same time, which is perfect.

I think this PR can be polished by adding a timer to the body of receiveBecomeActiveNote(). There is probably a reason why the app always waits 2 seconds before restarting (or even 10 after sleep), so adding 2 seconds of wait before starting listeners and setting loggedOut = false should prevent macOS from hanging.