Preserving of P8SCII Control Codes

(I believe you've yet to look at P8SCII, so this is just an FYI for when you do)

Currently, when picotool/luamin processes source files wish such code as below:
```lua
print("\^w\^thello world")
```

...it results in the backslashes being escaped (breaking the P8SCII Control Codes):
```lua
print("\\^w\\^thello world")
```