Sensors and controllers onboard:
Connected over I2C (/dev/i2c-0 on RPi model A and /dev/i2c-1 on RPi model B):
PCA9685 - 0x40
ADS1115 - 0x48
MPU9150 - 0x68
MS5611 - 0x77
MPU9150 compass (in pass-though mode) - 0x0C
Connected over SPI:
u-blox NEO-6T - /dev/spidev0.0
There are a lot of drivers in C/C++ and Python for these devices available over the internet from i2cdevlib, adafruit, sparkfun that will work with almost no modifications - just specify the correct address. We will try to make a compilation of them in the nearest future.
If you have any questions - feel free to ask them here.