Added an MIT license. Added TIM registers for STM32F4

I wasn't sure about the license. If you would prefer I use one of the BSD ones, I'm happy to change.

I also wasn't sure about the location.

I'll also need create an sstruct generator. I see 3 ways of doing this:
1 - add an option to yaml2h.py,
2 - copy yaml2h.py and create yaml2sstruct (or uctypes)
3 - factor common code out of yaml2h and create yaml2sstruct