Initial work on MPU-6050 device support

That's definitely not something ready to merge in, back a good start for Sparkfun MPU-6050 support.
I hope that thanks to this pull request someone can pick up where we finished.

Code was a part of a project at [Makerland](http://www.makerland.org/) hackathon.

/cc @zuchos @szimano @viroos