Many new things

[locusf]

Like:

• Tap on notifications to hide them
• Actually lock the screen by introducing a mousearea to lockscreen
• Notifications appear above statusbar
• Power button locking brings the lockscreen on top as it should
• Phone calls no longer linger in the background but are handled in a special layer instead
• Preliminary folder content showing
• Window close button is at a better place
• Sim panel hides when pin is entered correctly
• When a call is received, the alarm window should be swipeable away

[SfietKonstantin]

LGTM