SystemUI: Status bar clock - fixes

This commit fixes:

- no overlapping more from status bar icons on center clock.
  The width depending on what the user has setuped (date and clock) is exactly meassured now
- do not start animations if they are not needed
- reduce settings provider calls
- a bit cleanup

Change-Id: I7a37a6ae8f9bad0f265119af05dc20cf21cd6890
[1/2] Base: Hide power menu on lockscreen

Adds an option to enable/disable power menu on lockscreen.
policy: only disable power menu on secure lock screen
Merge branch 'L' of https://github.com/SimpleAOSP-Lollipop/platform_frameworks_base into L

Signed-off-by: CallMeAldy <aldrin.holmes20@gmail.com>

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/IconMerger.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java