Exit conditions don't respect when constants are set to 0

[ssejrog]

The code below, from PID.cpp, gets falsey triggered because those variables are not booleans.

  if (!(exit.small_error && exit.small_exit_time && exit.big_error && exit.big_exit_time && exit.velocity_exit_time && exit.mA_timeout)) {
    exit_condition_print(ERROR_NO_CONSTANTS);
    return ERROR_NO_CONSTANTS;
  }

This should be changed to

  if (exit.small_error == 0 && exit.small_exit_time == 0 && exit.big_error == 0 && exit.big_exit_time == 0 && exit.velocity_exit_time == 0 && exit.mA_timeout == 0) {
    exit_condition_print(ERROR_NO_CONSTANTS);
    return ERROR_NO_CONSTANTS;
  }