Add 2600 binary visualizer

[milnak]

Amazing extension.

I'd love to see a visualizer so that if I highight:

.byte $30
.byte $30
.byte $30
.byte $18
.byte $18
.byte $0C
.byte $4C
.byte $4C
.byte $7C
.byte $00

it displays something showing the (reversed) binary representation of bits:

|        |
| XXXXX  |
| X  XX  |
| X  XX  |
|    XX  |
|   XX   |
|   XX   |
|  XX    |
|  XX    |
|  XX    |

as this is how the 2600 stores character graphics.

[milnak]

similarly, for:

.byte $C6 
.byte $C6 
.byte $C6 
.byte $C6 
.byte $EE
.byte $EE
.byte $6C 
.byte $6C 
.byte $28  
.byte $28  
.byte $28  
.byte $28  

|  X X   |
|  X X   |
|  X X   |
|  X X   |
| XX XX  |
| XX XX  |
|XXX XXX |
|XXX XXX |
|XX   XX |
|XX   XX |
|XX   XX |
|XX   XX |