added src/luftboot to gitignore
fix locm3 library path: opencm3_stm32f1 lib is now directly in lib and not lib/stm32/f1
changed behaviour of luftboot to better match LPC21xx bootloader:
 * thanks to softsr (sergey krukowski) for starting the work
 * after payload upload, set flag and reset device
 * on boot, if upload just occurred, clear flag and jump to payload
 * if payload forced bootloader, start bootloader
 * if skip bootloader pin grounded, jump to payload
 * if USB vbus powered, start bootloader
 * otherwise, jump to payload
Either the external clock (12MHz PLL to 72MHz) or internal oscillator
(8MHz PLL to 48MHz) can be selected at build time. See README.
Updated to the new usb api in libopencm3.
Bumped version to 1.1