README.md: add serial and i2c functions
README.md: add serial and i2c functions

risebox/bonescript,theoctal/octalbonescript,il9ue/bonesimulator,il9ue/bonesimulator,risebox/bonescript,jadonk/bonescript,beagleboard/bonescript,beagleboard/bonescript,mwillbanks/octalbonescript,jadonk/bonescript