enable the Launcher3 settings button
Launcher3: add custom options pref screen

  ...this adds the option to select the default screen
Launcher3: default workspace improvements

clean up the default workspace as well as add tablet layouts sw600dp and sw720dp
TODO - clean up standard sized and sw600dp workspace
Launcher3: add a setting to remove the searchbar, hidden by default

also in this commit the search bar has been resized for sw720dp
Launcher3: Icon pack support

Some love for Launcher3 users
based on CMs Trebuchet and Burger

PS4
Add iconMask/iconBack/iconUpon/iconScale support

Change-Id: I2c3d29cfbceca060defd53980244e90dc46eb322

Conflicts:
	res/values/gummy_strings.xml
	src/com/android/launcher3/IconCache.java
	src/com/android/launcher3/LauncherPreferences.java
	src/com/android/launcher3/Utilities.java