Add boolean "not" and a "not equal" operator.

[Dunbaratu]

(This is a repeat of an issue that was just raised on the old KOS project just before erendrake and marionoapp merged their work into this project.)

1: Add a boolean unary negation operator, as in:

If not x = 2 { ... }.

or

if ! x = 2 { ... }.

2: Also the "not equal" operator seems to be missing from the otherwise complete list of comparators:
Implement either like this:

if x <> 2 {...}.

or like this

if x != 2 {...}.

[Dunbaratu]

To a certain extent, this is a "todo" for myself. I would like to implement this.

[marianoapp]

The minus sign already works as a boolean negation operator, so you can do something like:

if -(x = 2) { ... }.

[Dunbaratu]

Ugh. I'm not sure I like that solution, given the type-agnostic nature of kOS script. The idea of overloading 'minus' to sometimes mean "not" depending on if the operand is boolean or not is a bit 'iffy', since inversion in boolean symbols isn't represented with a minus sign.

[Dunbaratu]

pull request #46 now addresses this without the list index fix attached to it.

[marianoapp]

Closing as this was fixed in pull request #46.