Don't show "Eject card" if the card is not accessible

SD card is not accessible without removing the battery on some devices.
Remove the "Eject" options on those devices

Depends on http://review.cyanogenmod.org/62708

Change-Id: Iddfa72314f7c96579ddd98e8fb312236348b7c2d
Show "Eject card" for usb storage

Readd the "Eject" options if the SD card is mounted via usb.

Change-Id: I802cf4d20eb3b45ce068f89c22352f79999d593e
Settings: add key to USB Storage Unmount option

If we want to be able to highlight this preference and we need a key to do so.

Change-Id: I8c78f8cf8e75bbc071438ef4f733f3ac49e27791
Signed-off-by: Roman Birg <roman@cyngn.com>
Dont show "Erase SD Card" when there is none

On devices with physcal, external SD Cards, the "Erase SD card"
option in in Settings/Storage is available even when there is
no SD card present, this dont make much sense since you cannot
erase a card that is absent. With this change the erase option
is bound to the mount toggle which leads to the following
consequences:

 Card present and mounted -> Erase enabled
 Card present but unmounted -> Erase enabled
 No card present -> Erase disabled
 Card present and MTP attached -> Erase disabled

Change-Id: I756ae8af3e0565febaf940df5f4991dd89105bd9
Settings: Remove leftover from old theme chooser

Change-Id: Iaf97e2b94c27839eb4f9827a77917fe21a311b4c
Settings: Fix alignment of print settings icon

In case the print header row was not used for an account row before,
the print icon appeared shifted to the left.

Change-Id: Ieeafca0c16083f4a45b57a1015bb412da26bb0e9