[yocto] update mechanisms

[Mariano Lopez]

>> I
>> tried to summarize the key aspects of each mechanism in the table
>> itself. That's something that I haven't seen elsewhere and something
>> that the page can  I tried to be as fair and objective as possible,
>> please shout if I messed something up or you don't agree with my
>> summary.
>>
>> In particular the "complexity" column is a bit subjective. Stefano, I
>> hope you don't mind that I did not quite buy the "easy to use"
>> characterization of swupdate ;-)
> No worry...and I have not written myself. It was inserted by Mariano, so
> it looks like that swupdate at least for Mariano is "easy to use".
> I think it is correct to point out that customization is required.

Compared to other update mechanism that I tested it was the easier to
implement.