Add support for programming the SAM3X on the Udoo Quad

[arrys]

This PR adds support for a new board. The Udoo Quad or Dual. This board can be programmed from an external computer (1) or from the internal processor (2). I have therefore, added two new board configurations.

1. Udoo Quad
2. Udoo Quad Internal

The Udoo Quad needs a modifed bossac as it resets the SAM3X using a custom kernel module on the main processor. This means I also had to add the modified bossac tool in the manifest file.
This new tool is called when one of the Udoo board configurations is used.

This should be a step towards closing platformio/platformio-core#439.
I cannot add support for the Udoo Neo as I do not have access to the hardware to test it.

[arrys]

One note: I currently support bool-bossac-udoo on linux_x86_64 at my custom bossac fork but will add support for other platforms if this PR gets accepted.

I am happy to work out any issues.

[arrys]

I have currently tested the upload process in two scenarios.

1. Uploading from a linux x64(x86) host using the CN6 USB port.
2. Uploading from the SBC (linux armv7l) itself.

Both cases result in a succesful upload.

[mjbraun]

This should be a step towards closing platformio/platformio-core#439.
I cannot add support for the Udoo Neo as I do not have access to the hardware to test it.

Happy to run tests for you and report back, if that would help?

[arrys]

I have looked into the documentation for the Udoo Neo and it seems like there are 3 different ways to upload code.
Unfortunately I don't have the experience to get the Neo working.

I am not even sure this pull request is up to spec. I tried following all the rules I could find. It might be better to wait for someone from the core team to offer their view. I wouldn't want to force maintenance on them in case I don't fully understood the eco-system.