At the moment, the script install_duaboot does the following:
- rename SpiderApp to SpiderApp.of (unless it already exists)
- install payload as SpiderApp
- fixes permissions
Since SpiderApp is the main app, it will execute instead of the OF.
The current dualboot code (dualboot.c) is still a preliminary but the current
version displays an "all tools" menu to choose for. When exitting the menu
using BACK, it will run the OF.

With the modifications made by the install script, it should not be possible
to break the device. In the worst case scenario, the dualboot code crashes
and it restarted by the sysmgrd, or hangs. A safe way to recover is to plug
the USB cable and reset the device: the system manager will then start the
USB app and one can reflash the device if necessary.

Change-Id: Id9edab0347538ad2a8651a28aea7fd083feaa626

The new script allows the upgrade to execute a file found on the user partition.

Change-Id: I564941d01bcdbae050002e77cb119f3d95ecdc21

The exec_file allows to embed a script/executable and run it on target. It takes
of unpacking, remounting contents rw and redirect output to exec.txt at the root
of the drive. More generally, rework how the makefile works.

Change-Id: Iec719227be96e80701ad8f5398d2d34389f4da9e

Also fix a typo in the script makefile

Change-Id: Ie747d8b99ca0f6a98bbcaf1c82e66c7788f00e6e

Change-Id: I315d1010ce5477c0112f4a890156b360e8123e11