Adjust Launcher2 layouts to avoid big paddings in lower DPIs.

Homescreens part:
make the workspace fit the screen
adjust the padding in 600dp
recalculate the gaps
force recalculate the number of rows and cols

Appdrawer part:
make the drawer fit the screen
recalculate the number of rows and cols

Dock part:
adjust the padding

Edit: edited following Jesus' comments

Change-Id: I6ba905c698e1ba0b7b9d3ef2e66194d019625049