dfu-util: Support for DFU ST extensions (DfuSe)

[Tormod Volden]

Hi,

The code for supporting ST Microelectronics DFU extensions (DfuSe) is
now ready. It can be found in the dfuse-libusb-1.0 branch of
https://gitorious.org/~tormod/unofficial-clones/dfuse-dfu-util - I
recommend fetching it and viewing it with for instance "git instaweb"
instead of reading the commits on gitorious because they list the
commits out of commit order (I think they appear by author date and I
did some rebasing).

The code has been tested on several devices:
- DSO Nano pocket oscilloscope, whose IAP loader is based on STM32 USB
FS Device Library 1.0.
This was my original target application and many DSO Nano owners on
Linux or Mac have happily been using the early code. ST only provides
their own Windows loader application...
- Custom device using the DFU example in STM32 USB FS Device Library 3.1.0.
- STM32F107 which has a DFU boot loader in ROM (thanks Uwe Bonnes for
testing this!)
- STM32F105 was tested on an earlier version of the code (thanks
Sebastian Pfeiffer)

One question is if you prefer to merge my tree or just add the final
files (there are just small changes to main.c the rest is separate
files). My git history reflects the development from early hacks and
some back and forth changes and parallel development with master and
libusb-1.0 branches over time so they will mess up the "main" history.
On the other hand there is some explanations in the commit logs that
might help people understand things - ideally the code would be
self-explaining though. I am not sure what is the best way, I
originally thought I would submit the final files, but merging is part
of the power of git also...

My branch does not include updated documentation and man pages, I can
add this after the merge. I can also add more inline code
documentation at a later point.

Finally there are some outstanding patches that I have submitted for
the master branch. These are not needed for the DfuSe merge, but the
last in the list will currently not merge cleanly against the DfuSe
branch, so it should either be refreshed and applied after merging, or
I am happy to rebase the DfuSe branch after the patch has been applied
to master, to avoid merge conflicts. Actually, since that patch might
need some testing, I'd suggest to put it on hold. The rest is
relatively safe to apply.

55ae521 main: Make descriptor helper functions more generic
3d60f5b dfu-util.1: --device option never needed hex prefix
5d6e5a8 main: Move DFU state transition blocks together

Looking forward to your comments and to finally make the DfuSe support
"official"!

Cheers,
Tormod