Omap additions

All Omap additions developed during ardrone development. The I2C is not tested, it was only there in order to compile the very first time we started to develop on Paparazzi.

For reading the battery we do need I2C, so soon I will look at it a little better and take everything from i2c-dev.h in the ardrone_to_master branch, which is also a i2c library and compare it against i2c_arch.[ch].