Always let the launcher calculate the item gap in drawer
After calculating the number of cells to display, let the launcher determine the gap between cells so they doesn't appear stuck in the middle of the screen

Change-Id: If4b8893e223e3145344a286d97722f5dfce2c961
Fix: DoubleNumberPickerPreference was switching the default values

Change-Id: I8848af2c0c1af895370592d11aa3d99724db4b46
Adjust left and right paddings for TabletUI
In tablet ui, the launcher should have an extra padding in both sides so it looks more like stock launcher

Change-Id: Ic21accab28535f30aa5e02427c6a74d5c50d6dfd
Remove stretch screens preference
This option was useless since the screens always get stretched.

Change-Id: Icd203da90e128647d1073a9942998cb031f5ebb1
Pinch to enable expanded desktop

Change-Id: I8ea87b6eac8131c597d77089b754002da3ead444