SystemUI: ram bar and recents performance improvements

PS2: add SettingsObserver to eliminate the need for SysUI restart
PS3: tab derp
PS4: stop jumpy behavior when clicking recents fast!
PS5: more reasonable timeout
PS7: restore :)

Change-Id: Iee304142285757656129ab92542013196615a404
Signed-off-by: Roman Birg <romanbirg@gmail.com>

Conflicts:
	packages/SystemUI/src/com/android/systemui/liquid/LiquidTarget.java
	packages/SystemUI/src/com/android/systemui/recent/RecentsPanelView.java
	packages/SystemUI/src/com/android/systemui/statusbar/policy/ExtensibleKeyButtonView.java
SystemUI: fire off intent to preload along with first task

Seems to help bring it up faster~

Change-Id: I2115ad42a2fca4473f22a65ebfcdc20ac21bde5b
Signed-off-by: Roman Birg <romanbirg@gmail.com>