backend-driver: RuntimeError is misspelled
Merge pull request #71 from bgamari/master

backend-driver: Fix typo
examples: add broken i2c code
programmer: use right class in test code
lib/printf: add fixed point support
Revert "examples: add broken i2c code"

This reverts commit 67b060a2a35c46b9a43675fb8517187b25d22014.

Broke blink example code.
swd-adapter: change default pins

Update default SWD adapter pins to use PA0 for SWCLK and PA3 for SWDIO.
They are the default SWD target pins and are more likely be populated
anyways.
examples/printf: remove ruins
usb: allow copy transactions over 64 bytes

fixes #57
use env vars for ld, nm and objdump
retab, add __packed and fix interface index
low & high wValue byte fields
lib/usb: add descriptor generator tool
usb/gen-desc: update to working version
toolchain: add PIT peripheral