Setup main.plt to show what cmptest is doing.

Setup main.plt to show what cmptest is doing.

Does not function as expected. logicCpu.py simulation of cmptest with
user input thread disabled, and IN hardwired to 8 (10i):

-1:  cmp   1, -1
 0:  lwi  -3
  1:  cmp  -1,  1
{'A': -3, 'PC': 1, 'S': 1, 'OUT': 0, 'IN': 8}
{'A': -3, 'PC': -1, 'S': 1, 'OUT': 0, 'IN': 8}
{'A': -3, 'PC': 0, 'S': -1, 'OUT': 0, 'IN': 8}
{'A': -3, 'PC': 1, 'S': -1, 'OUT': 0, 'IN': 8}
{'A': -3, 'PC': -1, 'S': 1, 'OUT': 0, 'IN': 8}
{'A': -3, 'PC': 0, 'S': -1, 'OUT': 0, 'IN': 8}
{'A': -3, 'PC': 1, 'S': -1, 'OUT': 0, 'IN': 8}

Hardware results:
PC=0: A0=0, A1=i, A2=0, S=i
PC=1: A0=0, A1=0, A2=0, S=0
PC=i: A0=0, A1=0, A2=0, S=i

Somehow the A register is being latched with 0, when it really
should only store 3 (0i0, as it does at PC=0).

Status register is expected to go to 1, 1, i. Shouldn't hit 0
like it does, or stay at i like it does.