esp8266 i2c driver

This driver is far from perfect and still needs work, if you have any idears or questions please create a issue.

cd driver/
git clone https://github.com/zarya/esp8266_i2c_driver.git i2c

• Add #include "i2c/i2c.h" to your code
• Add driver/i2c to the MODULES line in the makefile