Stm32 cl

This patch set adds initial support for STM32F1x Connectivity Line devices using the libopencm3 ARM peripheral library and the CodeSourcery lite toolchain.  I have tested this with the STM32F107, and will add support for STM32F105 devices in the near future (slightly different memory maps).

Along with the CPU support, I have included a simple STM32F107 platform target.  Unfortunately my current devkit lacks an abundance of connectivity / storage peripherals, but I will be remedying that situation in the near future and will provide a more robust example platform.

The good:
-It works, and is tested using the standard contiki 'hello world' application, as well as a custom shell.
-Integration with libopencm3 works well
--This provides easy setup of all peripherals, and provides nice subsystem wrappers like CAN and USB

The bad:
-No ethernet networking / RTC included, though I will be adding both of these shortly (just need to get a more comprehensive devkit) 
-No storage examples.  Again, I need to buy a devkit which includes an SPI<>microSD slot before I can add this.