Beta/One: Introduce IS and ISN'T

[hostilefork]

In a language which purports to be an elegant rethinking of accidents of history, the historical behavior of = and == provide the worst of all worlds. The presence of the C derived == gives a suggestion that its complementary operator would be !=, while its complement is actually !==. Offering programmers an = operator which claims that %fOo = <FoO> is true and that to tell they are different you have to use %fOo !== <FoO> is bad.

This issue is to track the Beta/One objective of implementing the suggestion of using IS and ISN'T for lax equality and inequality (prefix is?, isn't?), and taking over = and <> for strict equality (which would be known as equal? and its complement, perhaps the boring not-equal?...(matches IF-NOT, WHILE-NOT) or the non-hyphenated unequal?, different? etc?

https://forum.rebol.info/t/strict-equality-lax-equality-equivalence-sameness-is-and/349/17

[hostilefork]

This is being reconsidered to a less invasive solution:

https://forum.rebol.info/t/compatibility-idea-is-and-isnt-replacing-and-not-and/1133