made the i2c files compile and added MPU6050 code from repo
Enable compiling of arduino MPU6050 code.
Implemented the Zaxis tracking code
changed the code so that the address is set within the constructor
changd the extentions to public so that they can be used in code
Added MPU6050 class to lib4774 namespace.

This allows the files from the Arduino version of the library to remain untouched
in their own subdirectory, and means the class name of 'MPU6050' can be
used without clashes.
Left shift device address to account for 8-bit requirement of WPILib I2C.
Don't try to implement reading words in I2Cdev - just fail.