Module 802.11 for Contiki-2.7

This code has been tested intensively with Arduino Due board using Atmel Studio Framework. It therefore includes Arduino CPU (SAM3X8E) and platform (Due) files and an example to configure the Wi-Fi module. 

- core/net/mac/ieee80211_ibss: 802.11 module
- cpu/arm/sam3x8e: sam3x8e CPU code - for Arduino Due
- platform/arduino/arduino-due: Arduino Due platform code
- examples/wifi-config: Wi-Fi configure example