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.
Initialise MPU6050 parent class inside constructor.
Allow MPU6050 to compile cleanly with DMP functions included.
Member functions of MPU6050 are not virtual.
Fixed constructors inMPU6050.
changed the axis trig variables into double return types
cleaned up the files a it by removing the arduino code
changed the copied files so that they are in the jrowberg namespace
uncommented the include of the 6Axis file in our MPU6050.cpp file