UI fixes to All apps pull up work

b/28917826
- nav bar change to light when top of the all apps container
passes y mid point of the status bar
- apps search edit box change when top of the all apps passes
the bottom of nav bar
- Restrict pull up to work only if the ACTION_DOWN event started
from the hotseat.
- Landscape: reverted old padding and margin. Only the interaction
is different.
- Tuning of the motion spec
- Animation duration respects fling speed more agressively.
- and many more small bugs...

Change-Id: Icde4093c41eeab8c9c6d9dc8b7d57adc3b171349

src/com/android/launcher3/allapps/VerticalPullDetector.java

@@ -135,7 +135,7 @@ public class VerticalPullDetector {
                 mDisplacementY = ev.getY() - mDownY;
                 mVelocity = computeVelocity(ev, mVelocity);
 
-                if (mState == State.SCROLLING && shouldRecatchScrollStart()){
+                if (mState == State.SCROLLING && Math.abs(mDisplacementY) > mTouchSlop ){
                     setState(State.DRAG);
                     reportScrollStart(true /* recatch */);
                 }