Operator matcher cuke needs to be rewritten/reorganized

Since #334 got merged, there are some inaccuracies in the operator matcher cuke file.

For example, it has this code in the narrative:

```
    expect(7).to == 7
    expect([1, 2, 3]).to == [1, 2, 3]
    expect("this is a string").to =~ /^this/
    expect("this is a string").not_to =~ /^that/
    expect(String).to === "this is a string"
```

But that doesn't work.  Operators can't be chained off of `expect(...).to`.

Also, it shows `expect(array).to =~ other_array` but that doesn't work either; with `expect`, only real, non-operator matchers work.  (The operator matchers require special handling due to precedence and we decided not to support them with `expect`).  `match_array` still works (as mentioned there) but it's not an operator matcher.

Given that operator matchers were for the old syntax, I'm not sure we need this file anymore.  However, we need to create a new file for `match_array` and possibly for the comparison matcher (e.g. `be < 5`) as those are still good APIs we want to support.