autoexec.sh starts a chroot in configos running update.sh

First of all copy all source files to USB mount point.

The update tool looks in the src folder for the update files:
    - mainos.tar.gz     + *.md5
    - configos.tar.gz   + *.md5
    - data.tar.gz       + *.md5
    - etc.tar.gz        + *.md5
    - factory.tar.gz    + *.md5
    - u-boot.img        + *.md5
    - MLO.img           + *.md5
    - splashimage.bin   + *.md5
    - machine.ini       + *.md5
    - pic_firmware.bin  + *.md5
    - fpga.bin          + *.md5
    - pic_firmware.bin  + *.md5
    - fram.bin          + *.md5


The etc partition is formatted in the following cases:
	1) A mainos update is required and the provided mainos version appears to be older then the one currently installed (downgrade)
	2) CFG_CLEAR_SETTINGS is set to 1

At the end of the process the user is asked to unplug the USB stick and manually power off the device to avoid update loops.

A log is saved in the usb stick as lastupdate.log.

To also generate a BSP backup the CFG_ENABLE_BACKUP variable has to be set to 1.
Files are generated inside a folder named backup_<date> with the corresponding *.md5

A space separated list of the components to backup can be specified in the CFG_BACKUP_COMPONENTS configuration variable

Possible values are:
    - mainos
    - configos
    - data
    - etc
    - factory
    - bootloader
    - xloader ( if supported )
    - splash ( if found )
    - machine ( if found )
    - pic ( if supported )
    - fpga ( if supported )
    - fram ( if supported )
	
For WCE7 components values are:
    - wce7_system 
    - wce7_data
    - wce7_package
    - wce7_registry
    - wce7_background


If CFG_BACKUP_COMPONENTS is not defined, the default components that will be saved are mainos, configos, data, etc, factory, bootloader, xloader and splash

ANDROID install support
------------------------
The possibility for installing the Android OS was added.
Android sources need to be placed into the "src/android" subfolder.

The required files are:
- system.tar.gz
- data.tar.gz 


WCE7 install support
------------------------
The possibility for installing the WCE7 OS was added.
WCE7 sources need to be placed into the "src/wce7" subfolder.

The supported files are:
- system.bin
- data.bin
- registry.tar.gz
- package.tar.gz
- background.bmp

The script (re)formats the involved partitions and copies/untars the required files.
