Add support for Unary Minus and Unary Plus

[NeeEoo]

Unary Plus is unneeded since it does nothing. Defined as +NUM
Unary Minus is defined as -NUM
They should not break BINOP.

[elikaski]

We don't have signed numbers

[NeeEoo]

Yea but it still might help to check if the number is negative such as -1. Currently you would do 0-1

[elikaski]

0-1 is 255
It is possible to support unary minus sign syntax-wise, but then we would have (-1 == 255) evaluate to true and so on
I don't know if it's a desired behavior... What do you think?

[NeeEoo]

The resulting bf code would be [-]- since the compiler shouldn't assume the cell size.
If i did 5-6 it would become -1. If it automatically set it to 255 and if the interpreter was 16-bit cells the check would fail.

[NeeEoo]

It would still be that 0-1 == 255. But for 16-bit interpreters it would be 0-1 == 65535

The compiler shouldn't convert -1 to the literal 255. It should use wrapping.