Add nextboot to set the selection from plugin.

- now we can change the bootimage selection from the plugin
bootmenu will show, and set the selection bar to the nextboot image.
kernel will be flashed if nextboot is different from selected
Add config for time duration to show bootmenu.

When nothing is set, then the default time of 5sec is used.
You can change the time in ../.timer (ex. write 15 for 15sec)
omb_utils: handle nandwrite/nanddump parameters for dreambox

When OMB_DREAMBOX is defined use nandwrite/nanddump parameters for dreambox.
We can define OMB_DREAMBOX using the following in bitbake:

${@base_contains("MACHINE_FEATURES", "dreambox", "-DOMB_DREAMBOX", "", d)}
Merge pull request #9 from athoik/dreambox

omb_utils: handle nandwrite/nanddump parameters for dreambox
omb_lcd: dreambox returns error on LCD_IOCTL_ASC_MODE
Merge pull request #10 from athoik/dreambox-lcd

omb_lcd: dreambox returns error on LCD_IOCTL_ASC_MODE