Added data frame definition for logger
Added data frame definition for logger

This dataframe is used to exchange data between microcontroller and
computer (basically python program)

It is possible from python program to (on the MCU) :
-read the table of available variables for logging (+name, +writing
permissions)
-read the value of a variable
-write the value to a parameter

Overdrivr/Freescale_Cup,Overdrivr/Freescale_Cup