Allow double-pressing power button to bypass home screen

This is related to bug #1384814. On my current phone, I love to the point of not wanting to give up the ability to:

1. When the phone is locked/screen off, double-press power button to bypass home screen and go immediately either the app at hand or alternatively to the unlock screen if the phone is currently locked.

2. When the phone has screen on, double-press power button to force enabling lock code even if the setting would be not to lock immediately.

This feature should not have any problematic consequences - at least on my current phone the possibility to double-click power has not ever posed any accidental problems and it does not affect the user experience if the person doesn't know about it. But the 2. can't be implemented naturally as long as the phone always locks itself anyway with a power press. This is requested to be only optional in bug #1384814.

The feature gives a lot of power to the user in situations where there's something "ongoing" in the sense that information on the phone is being used while on the move, for example constantly checking for navigation. Instead of power button + swipe + unlock code it's possible to just double-press power button and immediately see what's needed (provided locking is not enabled to be immediate without timeout). And then if the user is not having the phone locking immediately after screen off, it's still possible to force the locking when for example at a busy city center where there is a risk of a theft or such.

------- UX comment ------

We don't have something which allows number 2 to happen.

About number 1, design team doesn't dislike the idea, but it's very low priority and won't be spending time on it any time soon. It is up for grab if community wants to implement it, though.