Add option to configure how 'auto-unsuspend on focus' works

[deanoemcke]

This idea has come out of another github issue: #519 which related to an issue where a tab would not automatically unsuspend when it gained focus, if the focus was received due to another tab closing.
It would still auto-unsuspend if the tab was deliberately focused, but would ignore the focus event if it was indirectly given focus.

Currently in v7.0.109, the 'Automatically unsuspend tab when it is viewed' option will cause ALL tabs that gain focus to automatically unsuspend, regardless of wether the focus was direct or as a result of another tab closing.

There has been some interest (see issue: #114) for being able to manually configure this option for those that prefer the other behaviour.

[ossilator]

as one aspect of this, i'd like to be able to suppress auto-unsuspend when the window is focused - in such cases i often want to choose the right tab first, or the focusing was kinda accidental to start with ("clicking through" to the wrong mostly covered window).

[deanoemcke]

@ossilator I assume with this that you have the 'Never suspend active tab in each window' option unchecked.
I suspect that very few people have this option unchecked (it's checked by default). So the potential target users for such a feature would be very small.

[ossilator]

i did recently flip that option, but i have previously manually suspended the current/only tab, too.

generally, it might not be a good idea to have a lot of micro-options (at least on the forefront), but rather something like "usage profiles" that intelligently combine several options based on what the user wants to achieve (i haven't thought that trough; it might just be a one-dimensional measure of how aggressive the savings are supposed to be). that would automatically grow the groups of users that would actually make use of particular features.