Fix three automizer crashes

Two functions were failing to return promptly when receiving a null pointer, resulting in crashes. There was also a potential buffer overflow on creating a new automizer rule. These commits fix all of those issues.

The first of these patches (96e8a660) makes display_condition() check for NULL when negating a rule, so that it does not call itself again on a null pointer.

The second (2554b96b) makes condition_and_add() return immediately if either of its inputs are NULL. I've left the assert() statements in there as well, but they really should not be necessary any more.

The third (b4089643) makes sure to use the correct size for the name[] array when creating a new rule, so that the array does not overflow.