Implement dynamic fsync, read ahead and low memory killer

Change-Id: I995380aae86932ea00c21a9c0065d8bc04b0fe95
preferences: remove this stupidy, use a list for bootup restoring

Change-Id: I51e5ae05d7f64a6ebb40cad056d8681b1b8a27df
preferences: allow to toggle the way used for showing the menu

default is margin, which works like any usual navigation drawer
allows to use fullscreen / swipe on content, to swipe anywhere

Change-Id: Id9cced2e2a7b47a30dcd6d6ee3e2df5a74bfacb3
lmk: lets be nice and calculate the size for the user

Change-Id: I98a4d865e9594c4df35fadf41ad276fe00c849cd