General:
 - Changed brace style all over the project. Now curly braces start at a new line instead of the end of the line. It’s just more readable for me like this.

co_stack:
 - Added stack initialization which initializes node’s node ID, OD, PDO, SDO and state.
 - Added CAN message received handler.

test_appcycle:
 - Added heart beat processing in master.
 - Added SDO response processing in master.
 - Moved all of the slave CAN message receiving functionality to co_stack.