Version 0.22  - 17 March 2013
              - Added i2c interface to HiPi::Device::I2C (in addition to SMBus)
              - Added HiPi::BCM2835::I2C - i2c using registers direcly
              - Added HiPi::Interface::MPL3115A2 - to demonstrate repeated
                start operation using HiPi::BCM2835::I2C
              - Updated all i2c using interface modules to accept smbus, i2c
                or bcm2835 backends
Version 0.21  - 12 March 2013
              - HiPi::Device::OneWire read bug fixed
              - PWM Pin setting fixed in Control App
Version 0.20  - 11 March 2013
              - Refactored HiPi module tree