netduino-2 board with stm32f2

Netduino 2 stm32f2 using CDC.  Mostly being a copy of the STM32F4DISCOVERY with STM F2 libraries and pin changes.  CAN portion is not tested yet thus excluded in the board config.  Pin assignment is attached.

![netduino2elua](https://f.cloud.github.com/assets/1572460/905481/d5081e0a-fc2d-11e2-98ad-a68151fddaff.png)