add dualsystem support

Change-Id: Ief9f921fffe48b7586d75141286f00123cd080d9
show system-selection before confirm to install zip

Change-Id: I26b98233a8764b7c6a29977c70dbe75b11763362
verify_root_and_recovery for both systems

Change-Id: Iae0fab8c08682de5d3905f4a416cc75d85dbe7ba
patch real device-nodes instead of symlinks

Change-Id: If1973f7814806a5adaefe27036c31d0dd3c174ce
allow changing menu color

Change-Id: I0b78c1ec93fc13796f49c275c308192cf744aa61
add advanced option to change bootmode(system0 or system1)

Change-Id: I4d0f5bc971d334ca077bdb63d549373734140730
only show restore-options which are available for backup

Change-Id: Icda178b4a9c8f3ab80913e59f074a20cb167fa71
use correct initial_selection for filtered menu

Change-Id: I911f251a1559dd951c35e641f6475ecc10fe7e2d