Trebuchet: Centers vertically the wallpaper

Actually, the wallpaper is not center vertically (both, with wallpaperhack and
without wallpaperhack). This patch modifies:

* Replaces the WallpaperOffsetInterpolator class by the Launcher2 implementation.
* Fixes mWallpaperHack. onDraw now centers the y vertically.
* Disable mWallpaperHack when there is only one homescreen (otherwise a black screen is displayed).

Change-Id: Ia5e0763c9a31609db8f7826f619ed808041e97e7
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>

Conflicts:
	src/com/cyanogenmod/trebuchet/Workspace.java
Trebuchet: Fix vertical position of wallpaper when mWallpaperHack is activated

Fix vertical aligment of wallpaper when Wallpaper Quick Render setting is activated.
See http://review.cyanogenmod.org/35227

Change-Id: I3b2b7b59ebce995724bcc2fe3f2aa079c7abafee
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
Trebuchet: Fix NPE

This change fixes a NPE for the overflow menu. Steps:
1.- A device with no physical menu
2.- Install another launcher (xe Launcher2) (overflow menu is only displayed when Trebuchet runs
outside CM or when multiple launchers exists)
3.- Access AllAppDrawer and tap the overflow menu
4.- Tap again the overflow menu or rotate the screen and tap the overflow menu.
5.- NPE

The overflow menu is not recreated in onCreateOptionsMenu when isWorkspaceLocked(). The change
checks if the user is on the AllAppDrawer and forces the recreation of the menu.

Change-Id: Id68dd1f7b0c09a2f62b5f6d4fbef6f217bf98e82
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
Workspace and AppList Icon Tap/Touch
feedback improvement.

Improves (touch -> first highlight) latency.
Also saves upto 32-48 msecs in launch latencies.

Change-Id: I3ffdb629197489aa359cc1b3b75ebe7d62177d14