Change HTMLReporter symbols to be inline-block instead of floated

On a very large test suite (8000 specs), a significant amount of time is spent just drawing the spec dots. Some sort of worse-than-linear artifact that summons itself only when you have 8000 floated elements trying to hang out together.

This performance penalty is not seen with inline-block.

In Chrome 29:
  Floated dots: 16.795s
  Inline-block dots: 2.774s

Setting the dots to 'display: none;' takes about the same time as the inline-block figure, so this is probably a low enough bound (no need for chunked rendering or who knows what).

This is the amazing test suite I used in my profiling:
```
describe("Object A", function () {
  for (var i = 0; i < 8000; i++) {
    it("has a test numbered " + i.toString() + ", which is cool", function () {
      expect(1).toEqual(1);
    });
  }
});
```